Clear Don't Fragment bit on Linux

Question

I have a test requirement which required me clear don't fragment bit for packet flowing through Linux machine(cent-OS).

I have tried setting the net.ipv4.ip_forward_use_pmtu=1 but it seems to only disable MTU Path discovery and does not clear DF bit.

What is the method/approach to clear DF bit on packets?

Answer 1

sudo ip route add 192.168.1.0/24 dev ens36 mtu lock 1500

Simply lock mtu.