Hello everyone. I have a problem with configuration public static IP on my Ubuntu Server. I don't know what is wrong. I have 4 network interfaces from em1 to em4. I have connected em1 to LAN and em4 to WAN. Here is configuration in /etc/network/interfaces: # The primary network interface auto em1 em4 iface em1 inet static address 192.168.100.202 network 192.168.100.0 netmask 255.255.255.0 broadcast 192.168.100.255 #gateway 192.168.100.2 #this is not needed if below is configured gateway, am I right? dns-nameservers 192.168.100.2 iface em4 inet static address 31.X.X.180 network 31.X.X.176 #calculated from netmask and address netmask 255.255.255.248 gateway 31.X.X.177 dns-nameservers 193.X.X.10 193.X.X.20 Should I add some static routes or something? With this configuration I can't connect to the server from outside. Command 'route -n' in console gives output: Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 0.0.0.0 192.168.100.2 0.0.0.0 UG 0 0 0 em1 31.X.X.176 0.0.0.0 255.255.255.248 U 0 0 0 em4 192.168.100.0 0.0.0.0 255.255.255.0 U 0 0 0 em1