Hi all 
I have ROS 3.3
How can I set the firewall rule so that a certain IP is reached only by a certain class of IPs?
Tnx all 
Packet marking. Take a look at the load balancing wiki’s
Don’t care about load balancing.
The problem is more simple:
how can I allow packets (permit connections) only from certain class of IPs?
For example an SMTP server that permit connections only from class x.y.z.w.
tnx.
The information in the load balancing wikis will tell you how to mark packets which is what you need to do. Mark the packets from a certain range of ip’s and route them out gateway 1. Market the packets from the other range of IP’s and route them out gateway 2.
Go read the wiki.