On 3/6/18 3:10 AM, Stefano Brivio wrote: > Currently, administrative MTU changes on a given netdevice are > not reflected on route exceptions for MTU-less routes, with a > set PMTU value, for that device: > > # ip -6 route get 2001:db8::b > 2001:db8::b from :: dev vti_a proto kernel src 2001:db8::a metric 256 pref > medium > # ping6 -c 1 -q -s10000 2001:db8::b > /dev/null > # ip netns exec a ip -6 route get 2001:db8::b > 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 > cache expires 571sec mtu 4926 pref medium > # ip link set dev vti_a mtu 3000 > # ip -6 route get 2001:db8::b > 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 > cache expires 571sec mtu 4926 pref medium > # ip link set dev vti_a mtu 9000 > # ip -6 route get 2001:db8::b > 2001:db8::b from :: dev vti_a src 2001:db8::a metric 0 > cache expires 571sec mtu 4926 pref medium
Using your test script, I never see the route get an updated MTU -- it is always 1426. ++ exception='fd00:2::b from :: dev vti_a src fd00:2::a metric 0 expires 598sec mtu 1426 pref medium'
