Recover VPN/NAT Bridge

Owned by Bruno Chauvet (Unlicensed)
Last updated: Sept 27, 2016 by Arnaud Lachaume (Unlicensed)

If a VPN bridge box is restarted, it may happen that the sysctl setting net.ipv4.ip_forward is disabled
The symptoms are that the traffic will no longer be routed through the box (e.g. from one VPC to another, from the VPC to the internet). To fix this issue, run the following commands

sysctl -a | grep net.ipv4.ip_forward
> net.ipv4.ip_forward = 0
sudo sysctl -w net.ipv4.ip_forward=1
> net.ipv4.ip_forward = 1


For reference: http://fortycloud.com/interconnecting-two-aws-vpc-regions/