When routing traffic through a (IPSec) tunnel, an endpoint might need to do mss clamping if you are experiencing MTU issues. For example, you are using a site-to-site VPN network, with a specific gateway as endpoint. When browsing websites through the tunnel, some websites might not load properly. An example, using iptables to fix this… Continue reading TCP MSS clamping with iptables for IPSec tunnel
Month: November 2022
Multiple default gateways on Linux
Suppose you have a Linux machine doing IP forwarding (net.ipv4.ip_forward=1). Depending on the incoming traffic, you might want to forward the packets to different gateways. With just one gateway, you can simply add (or replace) the default gateway:ip route add default via x.x.x.x If you want to set a default gateway for a specific (incoming)… Continue reading Multiple default gateways on Linux