No embedded white-space is allowed.
Exclusion can appear after a list of addresses and/or address ranges. In that case, the final list of address is formed by taking the first list and then removing the addresses defined in the exclusion.
Beginning in Shorewall 4.4.13, the second form of exclusion is allowed after all and any in the SOURCE and DEST columns of /etc/shorewall/rules. It allows you to omit arbitrary zones from the list generated by those key words.
If you omit a sub-zone and there is an explicit or explicit CONTINUE policy, a connection to/from that zone can still be matched by the rule generated for a parent zone.
#ZONE TYPE z1 ip z2:z1 ip ...
#SOURCE DEST POLICY z1 net CONTINUE z2 net REJECT
#ACTION SOURCE DEST PROTO DEST # PORT(S) ACCEPT all!z2 net tcp 22
In this case, SSH connections from z2 to net will be accepted by the generated z1 to net ACCEPT rule.