Multiple discrete IP match rule - iptables

["Alano Stolf" <alano@stolf.com>]

I have not found any reference on how to specify more than one IP (discrete IPs, not a range) in an iptables rule.

For example, how can I log only the access to SMTP servers that are not the ones I may allow.

For instance, a rule like this should be fine:

iptables -A FORWARD -p tcp -d ! (IP_of_MySMTP_1 IP_of_MySMTP_2) --dport 25 -j LOG --log-prefix "Access to suspicious SMTP: "

 

Alano