Unknown Input Interface for Loopback IP in routed OSPF network after upgrade to 7.6

RouterOS General
1

Hi there,

i just upgrade a few devices from around 6.48 to 7.6. Apart from some minor adjustments i needed to do everything seems to work except some traffic to the loopback bridge ip which worked before.
Until now i allowed some traffic based on the input interface but this rule doesn’t get any hits anymore and the following is logged:

firewall: d_input input: in:(unknown 1) out:(unknown 0), connection-state:new proto ICMP (type 8, code 0), 10.8.192.65->10.12.192.24, len 56

Why is there no input interface? Did the logic changed in v7?

Even if i allow the traffic via a new firewall rule and check the Torch output for the specific interface it shows only tx icmp packets and no rx. Compared to a ping to the interface ip (not loopback bridge) i get both rx and tx:
mikrotik-loopback-error.png
Thanks for any hints,
Andy

2

Hi,

i did a few more tests and it seems to be related to mpls. With v7 packets to the loopback IP of an mpls enabled router is not bound to the correct input interface?!

I setup a lab according to https://wiki.mikrotik.com/wiki/Manual:MPLSVPLS with chr inside virtual box.
First with 6.49.7 which was working then 7.6 which was not working and after that i upgraded 6.49.7 to 7.6 and it also stopped working.

Until Log Entry 997 MPLS was enabled and after that i disabled it:
issue-test2.png
But i still don’t know if this is a bug or by design…