Hello! I have this configuration: a) A small server with this configuration: on eth1 - local network: 192.168.1.0/24 on eth0 10.100.122.90 to my ISP for tunneling inside his network to my big server. a gre tunnel 10.10.10.8 <-> 10.10.10.7 to my big server. I forward the network to my big server with unchanged addresses. b) A big server with 3 NICs: eth0 = $publicIP1 AND all 64 addresses form a $publicNET1 as aliases to eth0 eth1 = 192.168.101.1 connected to 192.168.101.0/24 AND 10.0.0.1 connected to 10.0.0.0/24 AND $publicIP2 as gateway for $publicNET2 tun1 = 10.10.10.7 <-> 10.10.10.8 tunnel to my small server i have this: publicNET1=1.2.3.0/26 iptables -t nat -A POSTROUTING -o eth0 -s 192.168.101.0/24 -j SNAT --to 1.2.3.1-1.2.3.32 # load balancing iptables -t nat -A POSTROUTING -o eth0 -s 10.0.0.0/24 -j SNAT --to 1.2.3.33-1.2.3.62 # load balancing iptables -t nat -A POSTROUTING -o eth0 -s 192.168.1.0 -j SNAT --to 1.2.3.1-1.2.3.62 # load balancing iptables -A FORWARD -s $publicNET2 -j ACCEPT iptables -A FORWARD -d $publicNET2 -j ACCEPT iptables -A FORWARD -i eth1 -s 192.168.101.0/24 -j ACCEPT iptables -A FORWARD -o eth1 -d 192.168.101.0/24 -j ACCEPT iptables -A FORWARD -i eth1 -s 10.0.0.0/24 -j ACCEPT iptables -A FORWARD -o eth1 -d 10.0.0.0/24 -j ACCEPT iptables -A FORWARD -i tun1 -s 192.168.1.0/24 -j ACCEPT iptables -A FORWARD -o tun1 -d 192.168.1.0/24 -j ACCEPT iptables -P FORWARD ACCEPT dns=ISP`s dns The ISP is providing a route from its internal 10.100.122.0 network to my $publicIP1 for tunneling. Problem: I can communicate with the Internet from the locally connected networks (192.168.101.0 and 10.0.0.0) but I have no access to the Internet for the tunneled network. >From the small server I can ping any machine on 192.168.101.0 or on 10.0.0.0. >From the big server I can ping any machine on the tunneled network. >From the small server I can ping ISP`s dns server. routes on small server: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.10.10.7 * 255.255.255.255 UH 0 0 0 tun1 ns.isp 10.100.122.65 255.255.255.255 UGH 0 0 0 eth0 $publicIP1.i 10.100.122.65 255.255.255.255 UGH 0 0 0 eth0 10.100.122.64 * 255.255.255.224 U 0 0 0 eth0 192.168.1.0 * 255.255.255.0 U 0 0 0 eth1 loopback * 255.0.0.0 U 0 0 0 lo default 10.10.10.7 0.0.0.0 UG 0 0 0 tun1 routes on big server: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 253.157.196.81. * 255.255.255.255 UH 0 0 0 eth1 253.157.196.81. * 255.255.255.255 UH 0 0 0 eth1 10.10.10.8 * 255.255.255.255 UH 0 0 0 tun1 $publicIP1 * 255.255.255.248 U 0 0 0 eth0 $publicNET2 * 255.255.255.248 U 0 0 0 eth1 $publicNET1 * 255.255.255.192 U 0 0 0 eth0 1.2.3.0 * 255.255.255.192 U 0 0 0 eth0 192.168.101.0 * 255.255.255.0 U 0 0 0 eth1 10.0.0.0 * 255.255.255.0 U 0 0 0 eth1 192.168.1.0 10.10.10.8 255.255.255.0 UG 0 0 0 tun1 loopback * 255.0.0.0 U 0 0 0 lo default $my_gw 0.0.0.0 UG 1 0 0 eth0 * Note that SNAT has overlapping addresses. I think that could be the problem. Has anyone experienced some similar situations? Thank you for your time, patience and help.
