Sorry for broad and ambiguous title. The case is:
I have 2 Network Cards, eth0 and eth1. OS: Ubuntu: 14.04. eth0 is configured with static address: 10.1.1.1 and provides WIFI, DHCP and DNS services so that other devices could connect to its WIFI. eth1 is configured as DHCP (/etc/network/interfaces) and connect to Internet.
Now the issue is a little bit confused:
Booting system with Internet cable plugged, everything works fine, and our services which run by Docker are working correctly. If unplugging cable, Docker containers cannot be restarted anymore (I mean, stop Docker containers first then up). Even ssh to the server (ssh ubuntu@10.1.200.1) is getting slower. Plug the cable back, everything back to normal. Manually stop eth1 and start it again (ifdown eth1 & ifup eth1) could fix this issue.
Booting system without Internet cable, the second Network Card cannot get a proper IP, and eth1:avahi comes up. No internet even if plug cable now. Do ifdown eth1 and eth1:avahi will be gone and everything back to normal.
In one word, the network seems been broken whenever unplug cable and have to re-activate eth1 to get it back.
I tried to take eth1 conf out of /etc/network/interfaces, so it should be managed by network-manager. But the issue still there. Need to use ifconfig to bring eth1 down and up in this case.
Hope I told the story clearly and someone could help.
