OPNsense Forum

English Forums => 26.7 Series => Topic started by: Denniz on July 16, 2026, 11:43:02 AM

Title: IPSEC OSPF opnsense 26.7
Post by: Denniz on July 16, 2026, 11:43:02 AM
Hi!

I upgraded to 26.7 and now OSPF in IPSEC dosent work for me.

I have an IPSEC VTI tunnel to a cisco router, the cisco router initiates the connection and the tunnel itself works. Since the update, OSPF just stops working some minutes and then comes back to life.

I see this in the OSPF logs - *** sendmsg in ospf_write failed to 224.0.0.5, id 0, off 0, len 120, interface ipsec10, mtu 1400: Network is unreachable

The network type is Point-to-multipoint and eveything worked before the upgrade, any clues?
Title: Re: IPSEC OSPF opnsense 26.7
Post by: nero355 on July 16, 2026, 02:55:27 PM
Quote from: Denniz on Today at 11:43:02 AMany clues?
I would say your MTU needs to be a bit lower, but I am not exactly the expert on the subject!

My expectation would be to see something like 1340 or so...


/EDIT :
Hmm... there seems to be something going on with IPSEC in general : https://forum.opnsense.org/index.php?topic=52415.0