Hello Jose, from the picture you provided the situation looks pretty simple. - you have enabled IP forwarding on router, I recommend you to put it into /etc/sysctl.conf for persistence. - you have configured firewall rules on router to allow forwarding traffic from left to right subnet. You can also try to set up ACCEPT policy just for testing. - the default gateway for left subnet is 192.168.1.1 (you mentioned router for Internet access). Correct me if I'm wrong. - the default gateway for right subnet I assume is 192.168.236.74. You don't have to do anything with routing here. Every host in right subnet knows where to send replies. - the problem seems to be missing routing information in left subnet. Hosts don't know anything about the right subnet and thus send requests to the default gateway 192.168.1.1. - modifying routing table on every host in left subnet can be solution in case, if there is only a few hosts which need to access right subnet - if you need to have fully accessible subnets, put the static route to default gateway 192.168.1.1 to redirect requests to proper gateway. If it is Linux gateway, try something like this [root at default-gw]# ip route add 192.168.236.0/24 via 192.168.236.74 Regards Andrej Jose Maria Terry Jimenez wrote: > I have a CentOS 5.5 machine with 2 nics each one configured to work in > one of the nets. The CentOS also uses a router for Internet access that > is 192.168.1.1. > > 192.168.1.0/24 >-----192.168.1.100--[CentOS Machine]--192.168.236.74 > --------< 192.168.236.0/24