need help with iproute2 and multiple NATs
In the past I got this to work, but on a new server I just built I cannot.
I have two networks set up on one interface.
eth4 is 192.168.0.1
eth4:0 is 192.168.1.1
I have two outgoing connections - eth3 is my cable modem, and ppp0 is a PPTP VPN.
I want workstations in the 192.168.0.0/24 network to use the cable modem, and workstations in the 192.168.1.0/24 network to use the VPN.
On my other server, I was using iproute2:
ifconfig eth4:0 192.168.1.1 netmask 255.255.255.0
ip route flush table 18
ip route add table 18 to 192.168.1.0/24 dev eth4:0
ip rule add from 192.168.1.0/24 table 18 priority 18
ip route flush cache
ip route add table 18 to default via $PPP_REMOTE dev ppp0
via iptables I masquerade traffic from 192.168.1.0/24 to ppp0:
iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -o ppp0 -j MASQUERADE
my 192.168.0.0/24 network is working fine. It's simply masqueraded in the same manner over eth3. traffic from 192.168.1.13 is not getting out, and I'm not sure what I'm missing here. like I said, masquerading/NAT works fine on this system, as 192.168.0.3 can get out to the internet without issue.
As you can see, I have three other ethernet interfaces in this box, so I could just move 192.168.1.1 to one of those and plug it into my switch and try that. And I might. But I am perplexed here, because this exact setup worked as I expected on my old server.
I'd been thinking of using multiple (physical) ethernet interfaces anyway, to increase the bandwidth from the server to the LAN. any advice here is appreciated. I enjoy system administration, but am an amateur, and I know it. :)