firehol-services(5) FireHOL services list

SYNOPSIS

AH all amanda any anystateless apcupsd apcupsdnis aptproxy asterisk

cups custom cvspserver

darkstat daytime dcc dcpp dhcp dhcprelay dhcpv6 dict distcc dns

echo emule eserver ESP

finger ftp

gift giftui gkrellmd GRE

h323 heartbeat http httpalt https hylafax

iax iax2 ICMP icmp ICMPV6 icmpv6 icp ident imap imaps ipsecnatt ipv6error ipv6mld ipv6neigh ipv6router irc isakmp

jabber jabberd

l2tp ldap ldaps lpd

microsoft_ds mms msn msnp ms_ds multicast mysql

netbackup netbios_dgm netbios_ns netbios_ssn nfs nis nntp nntps nrpe ntp nut nxserver

openvpn oracle OSPF

ping pop3 pop3s portmap postgres pptp privoxy

radius radiusold radiusoldproxy radiusproxy rdp rndc rsync rtp

samba sane sip smtp smtps snmp snmptrap socks squid ssh stun submission sunrpc swat syslog

telnet tftp time timestamp tomcat

upnp uucp

vmware vmwareauth vmwareweb vnc

webcache webmin whois

xbox xdmcp

DESCRIPTION

service: AH

IPSec Authentication Header (AH)
Example: 
  server AH accept

Service Type:

  • simple

Server Ports:

  • 51/any

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-AH]

Notes

For more information see this Archive of the FreeS/WAN documentation (http://web.archive.org/web/20100918134143/http://www.freeswan.org/freeswan_trees/freeswan-1.99/doc/ipsec.html#AH.ipsec) and RFC 2402 (http://www.ietf.org/rfc/rfc2402.txt). [WIKI-AH]: http://en.wikipedia.org/wiki/IPsec#Authentication_Header

service: all

Match all traffic
Example: 
  server all accept

Service Type:

  • simple

Server Ports:

  • all

Client Ports:

  • all

Netfilter Modules

Netfilter NAT Modules

Notes

Matches all traffic (all protocols, ports, etc.). Note that to provide "connections in one direction with replies" semantics, the kernel connection tracker is still used: this will therefore still not match packets if they are not understood as part of a connection (e.g. some ICMPv6 packets, requests and replies taking different routes, complex protocols with no helper loaded).

This service may indirectly setup a set of other services, if they require kernel modules to be loaded. The following complex services are activated:

service: amanda

Advanced Maryland Automatic Network Disk Archiver
Service Type:
  • simple

Server Ports:

  • udp/10080

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

service: any

Match all traffic (without modules or indirect)
Example: 
  server any *myname* accept proto 47

Service Type:

  • simple

Server Ports:

  • all

Client Ports:

  • all

Netfilter Modules

Netfilter NAT Modules

Notes

Matches all traffic (all protocols, ports, etc), but does not care about kernel modules and does not activate any other service indirectly. In combination with the firehol-params(5) this service can match unusual traffic (e.g. GRE - protocol 47).

Note that you have to supply your own name in addition to "any".

service: anystateless

Match all traffic statelessly
Example: 
  server anystateless *myname* accept proto 47

Service Type:

  • complex

Server Ports:

  • all

Client Ports:

  • all

Notes

Matches all traffic (all protocols, ports, etc), but does not care about kernel modules and does not activate any other service indirectly. In combination with the firehol-params(5) this service can match unusual traffic (e.g. GRE - protocol 47).

This service is identical to "any" but does not care about the state of traffic.

Note that you have to supply your own name in addition to "anystateless".

service: apcupsd

APC UPS Daemon
Example: 
  server apcupsd accept

Service Type:

  • simple

Server Ports:

  • tcp/6544

Client Ports:

  • default

Links

  • [Homepage][HOME-apcupsd]
  • [Wikipedia][WIKI-apcupsd]

Notes

This service must be defined as "server apcupsd accept" on all machines not directly connected to the UPS (i.e. slaves).

Note that the port defined here is not the default port (6666) used if you download and compile APCUPSD, since the default conflicts with IRC and many distributions (like Debian) have changed this to 6544.

You can define port 6544 in APCUPSD, by changing the value of NETPORT in its configuration file, or overwrite this FireHOL service definition using the procedures described in Adding Services in firehol.conf(5). [HOME-apcupsd]: http://www.apcupsd.com [WIKI-apcupsd]: http://en.wikipedia.org/wiki/Apcupsd

service: apcupsdnis

APC UPS Daemon Network Information Server
Example: 
  server apcupsdnis accept

Service Type:

  • simple

Server Ports:

  • tcp/3551

Client Ports:

  • default

Links

  • [Homepage][HOME-apcupsdnis]
  • [Wikipedia][WIKI-apcupsdnis]

Notes

This service allows the remote WEB interfaces of APCUPSD (http://www.apcupsd.com/), to connect and get information from the server directly connected to the UPS device. [HOME-apcupsdnis]: http://www.apcupsd.com [WIKI-apcupsdnis]: http://en.wikipedia.org/wiki/Apcupsd

service: aptproxy

Advanced Packaging Tool Proxy
Example: 
  server aptproxy accept

Service Type:

  • simple

Server Ports:

  • tcp/9999

Client Ports:

  • default

Links

service: asterisk

Asterisk PABX
Example: 
  server asterisk accept

Service Type:

  • simple

Server Ports:

  • tcp/5038

Client Ports:

  • default

Links

  • [Homepage][HOME-asterisk]
  • [Wikipedia][WIKI-asterisk]

Notes

This service refers only to the manager interface of asterisk. You should normally enable sip, h323, rtp, etc. at the firewall level, if you enable the relative channel drivers of asterisk. [HOME-asterisk]: http://www.asterisk.org [WIKI-asterisk]: http://en.wikipedia.org/wiki/Asterisk_PBX

service: cups

Common UNIX Printing System
Example: 
  server cups accept

Service Type:

  • simple

Server Ports:

  • tcp/631 udp/631

Client Ports:

  • any

Links

service: custom

Custom definitions
Example: 
  server custom myimap tcp/143 default accept

Service Type:

  • custom

Server Ports:

  • N/A

Client Ports:

  • N/A

Notes

The full syntax is:

subcommand custom name svr-proto/ports cli-ports action params

This service is used by FireHOL to allow you create rules for services which do not have a definition.

subcommand, action and params have their usual meanings.

A name must be supplied along with server ports in the form proto/range and client ports which takes only a range.

To define services with the built-in extension mechanism to avoid the need for custom services, see Adding Services in firehol.conf(5).

service: cvspserver

Concurrent Versions System
Example: 
  server cvspserver accept

Service Type:

  • simple

Server Ports:

  • tcp/2401

Client Ports:

  • default

Links

service: darkstat

Darkstat network traffic analyser
Example: 
  server darkstat accept

Service Type:

  • simple

Server Ports:

  • tcp/666

Client Ports:

  • default

Links

service: daytime

Daytime Protocol
Example: 
  server daytime accept

Service Type:

  • simple

Server Ports:

  • tcp/13

Client Ports:

  • default

Links

service: dcc

Distributed Checksum Clearinghouse
Example: 
  server dcc accept

Service Type:

  • simple

Server Ports:

  • udp/6277

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-dcc]

Notes

See also this DCC FAQ (http://www.rhyolite.com/dcc/FAQ.html#firewall-ports). [WIKI-dcc]: http://en.wikipedia.org/wiki/Distributed_Checksum_Clearinghouse

service: dcpp

Direct Connect++ P2P
Example: 
  server dcpp accept

Service Type:

  • simple

Server Ports:

  • tcp/1412 udp/1412

Client Ports:

  • default

Links

service: dhcp

Dynamic Host Configuration Protocol
Example: 
  server dhcp accept

Service Type:

  • complex

Server Ports:

  • udp/67

Client Ports:

  • 68

Links

  • [Wikipedia][WIKI-dhcp]

Notes

The dhcp service is implemented as stateless rules.

DHCP clients broadcast to the network (src 0.0.0.0 dst 255.255.255.255) to find a DHCP server. If the DHCP service was stateful the iptables connection tracker would not match the packets and deny to send the reply.

Note that this change does not affect the security of either DHCP servers or clients, since only the specific ports are allowed (there is no random port at either the server or the client side).

Note also that the "server dhcp accept" or "client dhcp accept" commands should placed within interfaces that do not have src and / or dst defined (because of the initial broadcast).

You can overcome this problem by placing the DHCP service on a separate interface, without a src or dst but with a policy return. Place this interface before the one that defines the rest of the services.

For example:

interface eth0 dhcp

policy return

server dhcp accept

interface eth0 lan src "$mylan" dst "$myip"

client all accept

For example: interface eth0 dhcp policy return server dhcp accept interface eth0 lan src "$mylan" dst "$myip" client all accept

This service implicitly sets its client or server to ipv4 mode. [WIKI-dhcp]: http://en.wikipedia.org/wiki/Dhcp

service: dhcprelay

DHCP Relay
Example: 
  server dhcprelay accept

Service Type:

  • simple

Server Ports:

  • udp/67

Client Ports:

  • 67

Links

  • [Wikipedia][WIKI-dhcprelay]

Notes

From RFC 1812 section 9.1.2:

In many cases, BOOTP clients and their associated BOOTP server(s) do not reside on the same IP (sub)network. In such cases, a third-party agent is required to transfer BOOTP messages between clients and servers. Such an agent was originally referred to as a BOOTP forwarding agent. However, to avoid confusion with the IP forwarding function of a router, the name BOOTP relay agent has been adopted instead.

For more information about DHCP Relay see section 9.1.2 of RFC 1812 (http://www.ietf.org/rfc/rfc1812.txt) and section 4 of RFC 1542 (http://www.ietf.org/rfc/rfc1542.txt) [WIKI-dhcprelay]: http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol#DHCP_relaying

service: dhcpv6

Dynamic Host Configuration Protocol for IPv6
Example: 
  server dhcp accept
  client dhcp accept

Service Type:

  • complex

Server Ports:

  • udp/547

Client Ports:

  • udp/546

Links

  • [Wikipedia][WIKI-dhcpv6]

Notes

The dhcp service is implemented as stateless rules. It cannot be stateful as the connection tracker will not match a unicast reply to a broadcast request. Further, if you wish to add src/dst rule parameters, you must account for both the broadcast and link-local network prefixes.

Clients broadcast from a link-local address to the multicast address ff02::1:2 on UDP port 547 to find a server. The server sends a unicast reply back to the client which listens on UDP port 546.

For a FireHOL interface, creating a client will allow sending to port 547 and receiving on port 546. Creating a server allows sending to port 546 and receiving on port 547.

Unlike DHCP for IPv4, the source ports to be used are not defined in DHCPv6 - see section 5.2 of RFC3315 (http://www.ietf.org/rfc/rfc3315.txt). Some servers are known to make use of this to send from arbitrary ports, so FireHOL does not assume a source port.

This service implicitly sets its client or server to ipv6 mode. [WIKI-dhcpv6]: https://en.wikipedia.org/wiki/DHCPv6

service: dict

Dictionary Server Protocol
Example: 
  server dict accept

Service Type:

  • simple

Server Ports:

  • tcp/2628

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-dict]

Notes

See RFC2229 (http://www.ietf.org/rfc/rfc2229.txt). [WIKI-dict]: http://en.wikipedia.org/wiki/DICT

service: distcc

Distributed CC
Example: 
  server distcc accept

Service Type:

  • simple

Server Ports:

  • tcp/3632

Client Ports:

  • default

Links

  • [Homepage][HOME-distcc]
  • [Wikipedia][WIKI-distcc]

Notes

For distcc security, please check the distcc security design (http://distcc.googlecode.com/svn/trunk/doc/web/security.html). [HOME-distcc]: https://code.google.com/p/distcc/ [WIKI-distcc]: http://en.wikipedia.org/wiki/Distcc

service: dns

Domain Name System
Example: 
  server dns accept

Service Type:

  • simple

Server Ports:

  • udp/53 tcp/53

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-dns]

Notes

On very busy DNS servers you may see a few dropped DNS packets in your logs. This is normal. The iptables connection tracker will timeout the session and lose unmatched DNS packets that arrive too late to be useful. [WIKI-dns]: http://en.wikipedia.org/wiki/Domain_Name_System

service: echo

Echo Protocol
Example: 
  server echo accept

Service Type:

  • simple

Server Ports:

  • tcp/7

Client Ports:

  • default

Links

service: emule

eMule (Donkey network client)
Example: 
  client emule accept src 192.0.2.1

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • many

Links

  • [Homepage][HOME-emule]

Notes

According to eMule Port Definitions (http://www.emule-project.net/home/perl/help.cgi?l=1&rm=show_topic&topic_id=122), FireHOL defines:

  • Accept from any client port to the server at tcp/4661
  • Accept from any client port to the server at tcp/4662
  • Accept from any client port to the server at udp/4665
  • Accept from any client port to the server at udp/4672
  • Accept from any server port to the client at tcp/4662
  • Accept from any server port to the client at udp/4672

Use the FireHOL firehol-client(5) command to match the eMule client.

Please note that the eMule client is an HTTP client also. [HOME-emule]: http://www.emule-project.com

service: eserver

eDonkey network server
Example: 
  server eserver accept

Service Type:

  • simple

Server Ports:

  • tcp/4661 udp/4661 udp/4665

Client Ports:

  • any

Links

service: ESP

IPSec Encapsulated Security Payload (ESP)
Example: 
  server ESP accept

Service Type:

  • simple

Server Ports:

  • 50/any

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-ESP]

Notes

For more information see this Archive of the FreeS/WAN documentation (http://web.archive.org/web/20100918134143/http://www.freeswan.org/freeswan_trees/freeswan-1.99/doc/ipsec.html#ESP.ipsec) RFC 2406 (http://www.ietf.org/rfc/rfc2406.txt). [WIKI-ESP]: http://en.wikipedia.org/wiki/IPsec#Encapsulating_Security_Payload

service: finger

Finger Protocol
Example: 
  server finger accept

Service Type:

  • simple

Server Ports:

  • tcp/79

Client Ports:

  • default

Links

service: ftp

File Transfer Protocol
Example: 
  server ftp accept

Service Type:

  • simple

Server Ports:

  • tcp/21

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

  • [Wikipedia][WIKI-ftp]

Notes

The FTP service matches both active and passive FTP connections. [WIKI-ftp]: http://en.wikipedia.org/wiki/Ftp

service: gift

giFT Internet File Transfer
Example: 
  server gift accept

Service Type:

  • simple

Server Ports:

  • tcp/4302 tcp/1214 tcp/2182 tcp/2472

Client Ports:

  • any

Links

  • [Homepage][HOME-gift]
  • [Wikipedia][WIKI-gift]

Notes

The gift FireHOL service supports:

  • Gnutella listening at tcp/4302
  • FastTrack listening at tcp/1214
  • OpenFT listening at tcp/2182 and tcp/2472

The above ports are the defaults given for the corresponding giFT modules.

To allow access to the user interface ports of giFT, use the giftui. [HOME-gift]: http://gift.sourceforge.net [WIKI-gift]: http://en.wikipedia.org/wiki/GiFT

service: giftui

giFT Internet File Transfer User Interface
Example: 
  server giftui accept

Service Type:

  • simple

Server Ports:

  • tcp/1213

Client Ports:

  • default

Links

  • [Homepage][HOME-giftui]
  • [Wikipedia][WIKI-giftui]

Notes

This service refers only to the user interface ports offered by giFT. To allow gift accept P2P requests, use the gift. [HOME-giftui]: http://gift.sourceforge.net [WIKI-giftui]: http://en.wikipedia.org/wiki/GiFT

service: gkrellmd

GKrellM Daemon
Example: 
  server gkrellmd accept

Service Type:

  • simple

Server Ports:

  • tcp/19150

Client Ports:

  • default

Links

service: GRE

Generic Routing Encapsulation
Example: 
  server GRE accept

Service Type:

  • simple

Server Ports:

  • 47/any

Client Ports:

  • any

Netfilter Modules

Netfilter NAT Modules

Links

  • [Wikipedia][WIKI-GRE]

Notes

Protocol No 47.

For more information see RFC RFC 2784 (http://www.ietf.org/rfc/rfc2784.txt). [WIKI-GRE]: http://en.wikipedia.org/wiki/Generic_Routing_Encapsulation

service: h323

H.323 VoIP
Example: 
  server h323 accept

Service Type:

  • simple

Server Ports:

  • udp/1720 tcp/1720

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

service: heartbeat

HeartBeat
Example: 
  server heartbeat accept

Service Type:

  • simple

Server Ports:

  • udp/690:699

Client Ports:

  • default

Links

  • [Homepage][HOME-heartbeat]

Notes

This FireHOL service has been designed such a way that it will allow multiple heartbeat clusters on the same LAN. [HOME-heartbeat]: http://www.linux-ha.org/

service: http

Hypertext Transfer Protocol
Example: 
  server http accept

Service Type:

  • simple

Server Ports:

  • tcp/80

Client Ports:

  • default

Links

service: httpalt

HTTP alternate port
Example: 
  server httpalt accept

Service Type:

  • simple

Server Ports:

  • tcp/8080

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-httpalt]

Notes

This port is commonly used by web servers, web proxies and caches where the standard http port is not available or can or should not be used. [WIKI-httpalt]: http://en.wikipedia.org/wiki/Http

service: https

Secure Hypertext Transfer Protocol
Example: 
  server https accept

Service Type:

  • simple

Server Ports:

  • tcp/443

Client Ports:

  • default

Links

service: hylafax

HylaFAX
Example: 
  server hylafax accept

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • many

Links

  • [Homepage][HOME-hylafax]
  • [Wikipedia][WIKI-hylafax]

Notes

This service allows incoming requests to server port tcp/4559 and outgoing from server port tcp/4558.

The correct operation of this service has not been verified.

USE THIS WITH CARE. A HYLAFAX CLIENT MAY OPEN ALL TCP UNPRIVILEGED PORTS TO ANYONE (from port tcp/4558). [HOME-hylafax]: http://www.hylafax.org/ [WIKI-hylafax]: http://en.wikipedia.org/wiki/Hylafax

service: iax

Inter-Asterisk eXchange
Example: 
  server iax accept

Service Type:

  • simple

Server Ports:

  • udp/5036

Client Ports:

  • default

Links

  • [Homepage][HOME-iax]
  • [Wikipedia][WIKI-iax]

Notes

This service refers to IAX version 1. There is also iax2. [HOME-iax]: http://www.asterisk.org [WIKI-iax]: http://en.wikipedia.org/wiki/Iax

service: iax2

Inter-Asterisk eXchange v2
Example: 
  server iax2 accept

Service Type:

  • simple

Server Ports:

  • udp/5469 udp/4569

Client Ports:

  • default

Links

  • [Homepage][HOME-iax2]
  • [Wikipedia][WIKI-iax2]

Notes

This service refers to IAX version 2. There is also iax. [HOME-iax2]: http://www.asterisk.org [WIKI-iax2]: http://en.wikipedia.org/wiki/Iax

service: ICMP

Internet Control Message Protocol
Example: 
  server ICMP accept

Service Type:

  • simple

Server Ports:

  • icmp/any

Client Ports:

  • any

Links

service: icmp

Internet Control Message Protocol
Alias for ICMP

service: ICMPV6

Internet Control Message Protocol v6
Example: 
  server ICMPV6 accept

Service Type:

  • simple

Server Ports:

  • icmpv6/any

Client Ports:

  • any

Links

service: icmpv6

Internet Control Message Protocol v6
Alias for ICMPV6

service: icp

Internet Cache Protocol
Example: 
  server icp accept

Service Type:

  • simple

Server Ports:

  • udp/3130

Client Ports:

  • 3130

Links

service: ident

Identification Protocol
Example: 
  server ident reject with tcp-reset

Service Type:

  • simple

Server Ports:

  • tcp/113

Client Ports:

  • default

Links

service: imap

Internet Message Access Protocol
Example: 
  server imap accept

Service Type:

  • simple

Server Ports:

  • tcp/143

Client Ports:

  • default

Links

service: imaps

Secure Internet Message Access Protocol
Example: 
  server imaps accept

Service Type:

  • simple

Server Ports:

  • tcp/993

Client Ports:

  • default

Links

service: ipsecnatt

NAT traversal and IPsec
Service Type:
  • simple

Server Ports:

  • udp/4500

Client Ports:

  • any

Links

service: ipv6error

ICMPv6 Error Handling
Example: 
  server ipv6error accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Notes

Not all icmpv6 error types should be treated equally inbound and outbound.

The ipv6error rule wraps all of them in the following way: * allow incoming messages only for existing sessions * allow outgoing messages always

The following ICMPv6 messages are handled:

  • destination-unreachable
  • packet-too-big
  • ttl-zero-during-transit
  • ttl-zero-during-reassembly
  • unknown-header-type
  • unknown-option

Interfaces should always have this set:

server ipv6error accept

In a router with inface being internal and outface being external the following will meet the recommendations of RFC 4890 (http://tools.ietf.org/html/rfc4890):

server ipv6error accept

Do not use: client ipv6error accept unless you are controlling traffic on a router interface where outface is the internal destination.

This service implicitly sets its client or server to ipv6 mode.

service: ipv6mld

IPv6 Multicast Listener Discovery for IPv6
Example: 
  client ipv6mld accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-ipv6mld]

Notes

IPv6 uses Multicast Listener Discovery to discover multicast listeners and what they are listening for.

In practice all IPv6 nodes are multicast listeners since multicast is used in the neighbour discovery protocol which replaces ARP in IPv4.

These rules are stateless since reports can happen automatically as well as on query.

Unless muticast snooping is disabled across the network, MLD should be enabled for any clients:

client ipv6mld accept

MLD should also be enabled as a server on any hosts acting as a router:

server ipv6mld accept

The rules should generally not be used to pass packets across a firewall (e.g. in a router definition) unless the firewall is for a bridge.

This service implicitly sets its client or server to ipv6 mode. [WIKI-ipv6mld]: https://en.wikipedia.org/wiki/Multicast_Listener_Discovery

service: ipv6neigh

IPv6 Neighbour discovery
Example: 
  client ipv6neigh accept
  server ipv6neigh accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-ipv6neigh]

Notes

IPv6 uses the Neighbour Discovery Protocol to do automatic configuration of routes and to replace ARP. To allow this functionality the network neighbour and router solicitation/advertisement messages should be enabled on each interface.

These rules are stateless since advertisement can happen automatically as well as on solicitation.

Neighbour discovery (incoming) should always be enabled:

server ipv6neigh accept

Neighbour advertisement (outgoing) should always be enabled:

client ipv6neigh accept

The rules should not be used to pass packets across a firewall (e.g. in a router definition) unless the firewall is for a bridge.

This service implicitly sets its client or server to ipv6 mode. [WIKI-ipv6neigh]: https://en.wikipedia.org/wiki/Neighbor_Discovery_Protocol

service: ipv6router

IPv6 Router discovery
Example: 
  client ipv6router accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-ipv6router]

Notes

IPv6 uses the Neighbour Discovery Protocol to do automatic configuration of routes and to replace ARP. To allow this functionality the network neighbour and router solicitation/advertisement messages should be enabled on each interface.

These rules are stateless since advertisement can happen automatically as well as on solicitation.

Router discovery (incoming) should always be enabled:

client ipv6router accept

Router advertisement (outgoing) should be enabled on a host that routes:

server ipv6router accept

The rules should not be used to pass packets across a firewall (e.g. in a router definition) unless the firewall is for a bridge.

This service implicitly sets its client or server to ipv6 mode. [WIKI-ipv6router]: https://en.wikipedia.org/wiki/Neighbor_Discovery_Protocol

service: irc

Internet Relay Chat
Example: 
  server irc accept

Service Type:

  • simple

Server Ports:

  • tcp/6667

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

service: isakmp

Internet Security Association and Key Management Protocol (IKE)
Example: 
  server isakmp accept

Service Type:

  • simple

Server Ports:

  • udp/500

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-isakmp]

Notes

For more information see the Archive of the FreeS/WAN documentation (http://web.archive.org/web/20100918134143/http://www.freeswan.org/freeswan_trees/freeswan-1.99/doc/ipsec.html#IKE.ipsec) [WIKI-isakmp]: http://en.wikipedia.org/wiki/ISAKMP

service: jabber

Extensible Messaging and Presence Protocol
Example: 
  server jabber accept

Service Type:

  • simple

Server Ports:

  • tcp/5222 tcp/5223

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-jabber]

Notes

Allows clear and SSL client-to-server connections. [WIKI-jabber]: http://en.wikipedia.org/wiki/Jabber

service: jabberd

Extensible Messaging and Presence Protocol (Server)
Example: 
  server jabberd accept

Service Type:

  • simple

Server Ports:

  • tcp/5222 tcp/5223 tcp/5269

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-jabberd]

Notes

Allows clear and SSL client-to-server and server-to-server connections.

Use this service for a jabberd server. In all other cases, use the jabber. [WIKI-jabberd]: http://en.wikipedia.org/wiki/Jabber

service: l2tp

Layer 2 Tunneling Protocol
Service Type:
  • simple

Server Ports:

  • udp/1701

Client Ports:

  • any

Links

service: ldap

Lightweight Directory Access Protocol
Example: 
  server ldap accept

Service Type:

  • simple

Server Ports:

  • tcp/389

Client Ports:

  • default

Links

service: ldaps

Secure Lightweight Directory Access Protocol
Example: 
  server ldaps accept

Service Type:

  • simple

Server Ports:

  • tcp/636

Client Ports:

  • default

Links

service: lpd

Line Printer Daemon Protocol
Example: 
  server lpd accept

Service Type:

  • simple

Server Ports:

  • tcp/515

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-lpd]

Notes

LPD is documented in RFC 1179 (http://www.ietf.org/rfc/rfc1179.txt).

Since many operating systems incorrectly use the non-default client ports for LPD access, this definition allows any client port to access the service (in addition to the RFC defined 721 to 731 inclusive). [WIKI-lpd]: http://en.wikipedia.org/wiki/Line_Printer_Daemon_protocol

service: microsoft_ds

Direct Hosted (NETBIOS-less) SMB
Example: 
  server microsoft_ds accept

Service Type:

  • simple

Server Ports:

  • tcp/445

Client Ports:

  • default

Notes

Direct Hosted (i.e. NETBIOS-less SMB)

This is another NETBIOS Session Service with minor differences with netbios_ssn. It is supported only by Windows 2000 and Windows XP and it offers the advantage of being independent of WINS for name resolution.

It seems that samba supports transparently this protocol on the netbios_ssn ports, so that either direct hosted or traditional SMB can be served simultaneously.

Please refer to the netbios_ssn for more information.

service: mms

Microsoft Media Server
Example: 
  server mms accept

Service Type:

  • simple

Server Ports:

  • tcp/1755 udp/1755

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

  • [Wikipedia][WIKI-mms]

Notes

Microsoft's proprietary network streaming protocol used to transfer unicast data in Windows Media Services (previously called NetShow Services). [WIKI-mms]: http://en.wikipedia.org/wiki/Microsoft_Media_Server

service: msn

Microsoft MSN Messenger Service
Example: 
  server msn accept

Service Type:

  • simple

Server Ports:

  • tcp/1863 udp/1863

Client Ports:

  • default

service: msnp

msnp
Example: 
  server msnp accept

Service Type:

  • simple

Server Ports:

  • tcp/6891

Client Ports:

  • default

service: ms_ds

Direct Hosted (NETBIOS-less) SMB
Alias for microsoft_ds

service: multicast

Multicast
Example: 
  server multicast reject with proto-unreach

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-multicast]

Notes

The multicast service matches all packets sent to the $MULTICAST_IPS addresses using IGMP or UDP. For IPv4 that means 224.0.0.0/4 and for IPv6 FF00::/16. [WIKI-multicast]: http://en.wikipedia.org/wiki/Multicast

service: mysql

MySQL
Example: 
  server mysql accept

Service Type:

  • simple

Server Ports:

  • tcp/3306

Client Ports:

  • default

Links

service: netbackup

Veritas NetBackup service
Example: 
  server netbackup accept
  client netbackup accept

Service Type:

  • simple

Server Ports:

  • tcp/13701 tcp/13711 tcp/13720 tcp/13721 tcp/13724 tcp/13782 tcp/13783

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-netbackup]

Notes

To use this service you must define it as both client and server in NetBackup clients and NetBackup servers. [WIKI-netbackup]: http://en.wikipedia.org/wiki/Netbackup

service: netbios_dgm

NETBIOS Datagram Distribution Service
Example: 
  server netbios_dgm accept

Service Type:

  • simple

Server Ports:

  • udp/138

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-netbios_dgm]

Notes

See also the samba.

Keep in mind that this service broadcasts (to the broadcast address of your LAN) UDP packets. If you place this service within an interface that has a dst parameter, remember to include (in the dst parameter) the broadcast address of your LAN too. [WIKI-netbios_dgm]: http://en.wikipedia.org/wiki/Netbios#Datagram_distribution_service

service: netbios_ns

NETBIOS Name Service
Example: 
  server netbios_ns accept

Service Type:

  • simple

Server Ports:

  • udp/137

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-netbios_ns]

Notes

See also the samba. [WIKI-netbios_ns]: http://en.wikipedia.org/wiki/Netbios#Name_service

service: netbios_ssn

NETBIOS Session Service
Example: 
  server netbios_ssn accept

Service Type:

  • simple

Server Ports:

  • tcp/139

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-netbios_ssn]

Notes

See also the samba.

Please keep in mind that newer NETBIOS clients prefer to use port 445 (microsoft_ds) for the NETBIOS session service, and when this is not available they fall back to port 139 (netbios_ssn). Versions of samba above 3.x bind automatically to ports 139 and 445.

If you have an older samba version and your policy on an interface or router is DROP, clients trying to access port 445 will have to timeout before falling back to port 139. This timeout can be up to several minutes.

To overcome this problem you can explicitly REJECT the microsoft_ds with a tcp-reset message:

server microsoft_ds reject with tcp-reset [WIKI-netbios_ssn]: http://en.wikipedia.org/wiki/Netbios#Session_service

service: nfs

Network File System
Example: 
  client nfs accept dst 192.0.2.1

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • N/A

Links

Notes

The NFS service queries the RPC service on the NFS server host to find out the ports nfsd, mountd, lockd and rquotad are listening. Then, according to these ports it sets up rules on all the supported protocols (as reported by RPC) in order the clients to be able to reach the server.

For this reason, the NFS service requires that:

  • the firewall is restarted if the NFS server is restarted
  • the NFS server must be specified on all nfs statements (only if it is not the localhost)

Since NFS queries the remote RPC server, it is required to also be allowed to do so, by allowing the portmap too. Take care that this is allowed by the running firewall when FireHOL tries to query the RPC server. So you might have to setup NFS in two steps: First add the portmap service and activate the firewall, then add the NFS service and restart the firewall.

To avoid this you can setup your NFS server to listen on pre-defined ports, as documented in NFS Howto (http://nfs.sourceforge.net/nfs-howto/ar01s06.html#nfs_firewalls). If you do this then you will have to define the the ports using the procedure described in Adding Services in firehol.conf(5).

service: nis

Network Information Service
Example: 
  client nis accept dst 192.0.2.1

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-nis]

Notes

The nis service queries the RPC service on the nis server host to find out the ports ypserv and yppasswdd are listening. Then, according to these ports it sets up rules on all the supported protocols (as reported by RPC) in order the clients to be able to reach the server.

For this reason, the nis service requires that:

  • the firewall is restarted if the nis server is restarted
  • the nis server must be specified on all nis statements (only if it is not the localhost)

Since nis queries the remote RPC server, it is required to also be allowed to do so, by allowing the portmap too. Take care that this is allowed by the running firewall when FireHOL tries to query the RPC server. So you might have to setup nis in two steps: First add the portmap service and activate the firewall, then add the nis service and restart the firewall.

This service was added to FireHOL by Carlos Rodrigues (http://sourceforge.net/p/firehol/feature-requests/20/). His comments regarding this implementation, are:

These rules work for client access only!

Pushing changes to slave servers won't work if these rules are active somewhere between the master and its slaves, because it is impossible to predict the ports where yppush will be listening on each push.

Pulling changes directly on the slaves will work, and could be improved performance-wise if these rules are modified to open fypxfrd. This wasn't done because it doesn't make that much sense since pushing changes on the master server is the most common, and recommended, way to replicate maps. [WIKI-nis]: http://en.wikipedia.org/wiki/Network_Information_Service

service: nntp

Network News Transfer Protocol
Example: 
  server nntp accept

Service Type:

  • simple

Server Ports:

  • tcp/119

Client Ports:

  • default

Links

service: nntps

Secure Network News Transfer Protocol
Example: 
  server nntps accept

Service Type:

  • simple

Server Ports:

  • tcp/563

Client Ports:

  • default

Links

service: nrpe

Nagios NRPE
Service Type:
  • simple

Server Ports:

  • tcp/5666

Client Ports:

  • default

Links

service: ntp

Network Time Protocol
Example: 
  server ntp accept

Service Type:

  • simple

Server Ports:

  • udp/123 tcp/123

Client Ports:

  • any

Links

service: nut

Network UPS Tools
Example: 
  server nut accept

Service Type:

  • simple

Server Ports:

  • tcp/3493 udp/3493

Client Ports:

  • default

Links

service: nxserver

NoMachine NX Server
Example: 
  server nxserver accept

Service Type:

  • simple

Server Ports:

  • tcp/5000:5200

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-nxserver]

Notes

Default ports used by NX server for connections without encryption.

Note that nxserver also needs the ssh to be enabled.

This information has been extracted from this The TCP ports used by nxserver are 4000 + DISPLAY_BASE to 4000 + DISPLAY_BASE + DISPLAY_LIMIT. DISPLAY_BASE and DISPLAY_LIMIT are set in /usr/NX/etc/node.conf and the defaults are DISPLAY_BASE=1000 and DISPLAY_LIMIT=200.

For encrypted nxserver sessions, only ssh is needed. [WIKI-nxserver]: http://en.wikipedia.org/wiki/NX_Server

service: openvpn

OpenVPN
Service Type:
  • simple

Server Ports:

  • tcp/1194 udp/1194

Client Ports:

  • default

Links

service: oracle

Oracle Database
Example: 
  server oracle accept

Service Type:

  • simple

Server Ports:

  • tcp/1521

Client Ports:

  • default

Links

service: OSPF

Open Shortest Path First
Example: 
  server OSPF accept

Service Type:

  • simple

Server Ports:

  • 89/any

Client Ports:

  • any

Links

service: ping

Ping (ICMP echo)
Example: 
  server ping accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-ping]

Notes

This services matches requests of protocol ICMP and type echo-request (TYPE=8) and their replies of type echo-reply (TYPE=0).

The ping service is stateful. [WIKI-ping]: http://en.wikipedia.org/wiki/Ping

service: pop3

Post Office Protocol
Example: 
  server pop3 accept

Service Type:

  • simple

Server Ports:

  • tcp/110

Client Ports:

  • default

Links

service: pop3s

Secure Post Office Protocol
Example: 
  server pop3s accept

Service Type:

  • simple

Server Ports:

  • tcp/995

Client Ports:

  • default

Links

service: portmap

Open Network Computing Remote Procedure Call - Port Mapper
Example: 
  server portmap accept

Service Type:

  • simple

Server Ports:

  • udp/111 tcp/111

Client Ports:

  • any

Links

service: postgres

PostgreSQL
Example: 
  server postgres accept

Service Type:

  • simple

Server Ports:

  • tcp/5432

Client Ports:

  • default

Links

service: pptp

Point-to-Point Tunneling Protocol
Example: 
  server pptp accept

Service Type:

  • simple

Server Ports:

  • tcp/1723

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

service: privoxy

Privacy Proxy
Example: 
  server privoxy accept

Service Type:

  • simple

Server Ports:

  • tcp/8118

Client Ports:

  • default

Links

service: radius

Remote Authentication Dial In User Service (RADIUS)
Example: 
  server radius accept

Service Type:

  • simple

Server Ports:

  • udp/1812 udp/1813

Client Ports:

  • default

Links

service: radiusold

Remote Authentication Dial In User Service (RADIUS)
Example: 
  server radiusold accept

Service Type:

  • simple

Server Ports:

  • udp/1645 udp/1646

Client Ports:

  • default

Links

service: radiusoldproxy

Remote Authentication Dial In User Service (RADIUS)
Example: 
  server radiusoldproxy accept

Service Type:

  • simple

Server Ports:

  • udp/1647

Client Ports:

  • default

Links

service: radiusproxy

Remote Authentication Dial In User Service (RADIUS)
Example: 
  server radiusproxy accept

Service Type:

  • simple

Server Ports:

  • udp/1814

Client Ports:

  • default

Links

service: rdp

Remote Desktop Protocol
Example: 
  server rdp accept

Service Type:

  • simple

Server Ports:

  • tcp/3389

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-rdp]

Notes

Remote Desktop Protocol is also known also as Terminal Services. [WIKI-rdp]: http://en.wikipedia.org/wiki/Remote_Desktop_Protocol

service: rndc

Remote Name Daemon Control
Example: 
  server rndc accept

Service Type:

  • simple

Server Ports:

  • tcp/953

Client Ports:

  • default

Links

service: rsync

rsync protocol
Example: 
  server rsync accept

Service Type:

  • simple

Server Ports:

  • tcp/873 udp/873

Client Ports:

  • default

Links

service: rtp

Real-time Transport Protocol
Example: 
  server rtp accept

Service Type:

  • simple

Server Ports:

  • udp/10000:20000

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-rtp]

Notes

RTP ports are generally all the UDP ports. This definition narrows down RTP ports to UDP 10000 to 20000. [WIKI-rtp]: http://en.wikipedia.org/wiki/Real-time_Transport_Protocol

service: samba

Samba
Example: 
  server samba accept

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • default

Links

  • [Homepage][HOME-samba]
  • [Wikipedia][WIKI-samba]

Notes

The samba service automatically sets all the rules for netbios_ns, netbios_dgm, netbios_ssn and microsoft_ds.

Please refer to the notes of the above services for more information.

NETBIOS initiates based on the broadcast address of an interface (request goes to broadcast address) but the server responds from its own IP address. This makes the "server samba accept" statement drop the server reply, because of the way the iptables connection tracker works.

This service definition includes a hack, that allows a Linux samba server to respond correctly in such situations, by allowing new outgoing connections from the well known netbios_ns port to the clients high ports.

However, for clients and routers this hack is not applied because it would open all unprivileged ports to the samba server. The only solution to overcome the problem in such cases (routers or clients) is to build a trust relationship between the samba servers and clients. [HOME-samba]: http://www.samba.org/ [WIKI-samba]: http://en.wikipedia.org/wiki/Samba_(software)

service: sane

SANE Scanner service
Service Type:
  • simple

Server Ports:

  • tcp/6566

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

  • N/A

Links

service: sip

Session Initiation Protocol
Example: 
  server sip accept

Service Type:

  • simple

Server Ports:

  • tcp/5060 udp/5060

Client Ports:

  • 5060 default

Netfilter Modules

Netfilter NAT Modules

Links

  • [Wikipedia][WIKI-sip]

Notes

SIP (http://www.voip-info.org/wiki/view/SIP) is an IETF standard protocol (RFC 2543) for initiating interactive user sessions involving multimedia elements such as video, voice, chat, gaming, etc. SIP works in the application layer of the OSI communications model. [WIKI-sip]: http://en.wikipedia.org/wiki/Session_Initiation_Protocol

service: smtp

Simple Mail Transport Protocol
Example: 
  server smtp accept

Service Type:

  • simple

Server Ports:

  • tcp/25

Client Ports:

  • default

Links

service: smtps

Secure Simple Mail Transport Protocol
Example: 
  server smtps accept

Service Type:

  • simple

Server Ports:

  • tcp/465

Client Ports:

  • default

Links

service: snmp

Simple Network Management Protocol
Example: 
  server snmp accept

Service Type:

  • simple

Server Ports:

  • udp/161

Client Ports:

  • default

Links

service: snmptrap

SNMP Trap
Example: 
  server snmptrap accept

Service Type:

  • simple

Server Ports:

  • udp/162

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-snmptrap]

Notes

An SNMP trap is a notification from an agent to a manager. [WIKI-snmptrap]: http://en.wikipedia.org/wiki/Simple_Network_Management_Protocol#Trap

service: socks

SOCKet Secure
Example: 
  server socks accept

Service Type:

  • simple

Server Ports:

  • tcp/1080 udp/1080

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-socks]

Notes

See also RFC 1928 (http://www.ietf.org/rfc/rfc1928.txt). [WIKI-socks]: http://en.wikipedia.org/wiki/SOCKS

service: squid

Squid Web Cache
Example: 
  server squid accept

Service Type:

  • simple

Server Ports:

  • tcp/3128

Client Ports:

  • default

Links

service: ssh

Secure Shell Protocol
Example: 
  server ssh accept

Service Type:

  • simple

Server Ports:

  • tcp/22

Client Ports:

  • default

Links

service: stun

Session Traversal Utilities for NAT
Example: 
  server stun accept

Service Type:

  • simple

Server Ports:

  • udp/3478 udp/3479

Client Ports:

  • any

Links

  • [Wikipedia][WIKI-stun]

Notes

STUN (http://www.voip-info.org/wiki/view/STUN) is a protocol for assisting devices behind a NAT firewall or router with their packet routing. [WIKI-stun]: http://en.wikipedia.org/wiki/STUN

service: submission

SMTP over SSL/TLS submission
Example: 
  server submission accept

Service Type:

  • simple

Server Ports:

  • tcp/587

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-submission]

Notes

Submission is essentially normal SMTP with an SSL/TLS negotiation. [WIKI-submission]: http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol

service: sunrpc

Open Network Computing Remote Procedure Call - Port Mapper
Alias for portmap

service: swat

Samba Web Administration Tool
Example: 
  server swat accept

Service Type:

  • simple

Server Ports:

  • tcp/901

Client Ports:

  • default

Links

service: syslog

Syslog Remote Logging Protocol
Example: 
  server syslog accept

Service Type:

  • simple

Server Ports:

  • udp/514

Client Ports:

  • 514 default

Links

service: telnet

Telnet
Example: 
  server telnet accept

Service Type:

  • simple

Server Ports:

  • tcp/23

Client Ports:

  • default

Links

service: tftp

Trivial File Transfer Protocol
Example: 
  server tftp accept

Service Type:

  • simple

Server Ports:

  • udp/69

Client Ports:

  • default

Netfilter Modules

Netfilter NAT Modules

Links

service: time

Time Protocol
Example: 
  server time accept

Service Type:

  • simple

Server Ports:

  • tcp/37 udp/37

Client Ports:

  • default

Links

service: timestamp

ICMP Timestamp
Example: 
  server timestamp accept

Service Type:

  • complex

Server Ports:

  • N/A

Client Ports:

  • N/A

Links

  • [Wikipedia][WIKI-timestamp]

Notes

This services matches requests of protocol ICMP and type timestamp-request (TYPE=13) and their replies of type timestamp-reply (TYPE=14).

The timestamp service is stateful. [WIKI-timestamp]: http://en.wikipedia.org/wiki/Internet_Control_Message_Protocol#Timestamp

service: tomcat

HTTP alternate port
Alias for httpalt

service: upnp

Universal Plug and Play
Example: 
  server upnp accept

Service Type:

  • simple

Server Ports:

  • udp/1900 tcp/2869

Client Ports:

  • default

Links

  • [Homepage][HOME-upnp]
  • [Wikipedia][WIKI-upnp]

Notes

For a Linux implementation see: Linux IGD (http://linux-igd.sourceforge.net/). [HOME-upnp]: http://upnp.sourceforge.net/ [WIKI-upnp]: http://en.wikipedia.org/wiki/Universal_Plug_and_Play

service: uucp

Unix-to-Unix Copy
Example: 
  server uucp accept

Service Type:

  • simple

Server Ports:

  • tcp/540

Client Ports:

  • default

Links

service: vmware

vmware
Example: 
  server vmware accept

Service Type:

  • simple

Server Ports:

  • tcp/902

Client Ports:

  • default

Notes

Used from VMWare 1 and up. See the VMWare KnowledgeBase (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012382).

service: vmwareauth

vmwareauth
Example: 
  server vmwareauth accept

Service Type:

  • simple

Server Ports:

  • tcp/903

Client Ports:

  • default

Notes

Used from VMWare 1 and up. See the VMWare KnowledgeBase (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012382).

service: vmwareweb

vmwareweb
Example: 
  server vmwareweb accept

Service Type:

  • simple

Server Ports:

  • tcp/8222 tcp/8333

Client Ports:

  • default

Notes

Used from VMWare 2 and up. See VMWare Server 2.0 release notes (http://www.vmware.com/support/server2/doc/releasenotes_vmserver2.html) and the VMWare KnowledgeBase (http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1012382).

service: vnc

Virtual Network Computing
Example: 
  server vnc accept

Service Type:

  • simple

Server Ports:

  • tcp/5900:5903

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-vnc]

Notes

VNC is a graphical desktop sharing protocol. [WIKI-vnc]: http://en.wikipedia.org/wiki/Virtual_Network_Computing

service: webcache

HTTP alternate port
Alias for httpalt

service: webmin

Webmin Administration System
Example: 
  server webmin accept

Service Type:

  • simple

Server Ports:

  • tcp/10000

Client Ports:

  • default

Links

service: whois

WHOIS Protocol
Example: 
  server whois accept

Service Type:

  • simple

Server Ports:

  • tcp/43

Client Ports:

  • default

Links

service: xbox

Xbox Live
Example: 
  client xbox accept

Service Type:

  • complex

Server Ports:

  • many

Client Ports:

  • default

Notes

Definition for the Xbox live service.

See program source for contributor details.

service: xdmcp

X Display Manager Control Protocol
Example: 
  server xdmcp accept

Service Type:

  • simple

Server Ports:

  • udp/177

Client Ports:

  • default

Links

  • [Wikipedia][WIKI-xdmcp]

Notes

See Gnome Display Manager (http://www.jirka.org/gdm-documentation/x70.html) for a discussion about XDMCP and firewalls (Gnome Display Manager is a replacement for XDM). [WIKI-xdmcp]: http://en.wikipedia.org/wiki/X_display_manager_(program_type)#X_Display_Manager_Control_Protocol

AUTHORS

FireHOL Team.

LAST SEARCHED