forgot to add misc@ ...
On Mon, Apr 13, 2020 at 11:18:17AM +0200, Remi Locherer wrote:
> Hi Richard,
>
> On Mon, Apr 13, 2020 at 08:38:31AM +0100, Richard Chivers wrote:
> > We have been having a strange issue, whereby OSPF stops updating properly.
> >
> > We can see an entry for an ip route in the database but it is not in the
> > kernel routing table, and when it is the DR, other routers then do not have
> > the route at all.
> >
> > We are seeing this across multiple boxes. We have 10+ ospf speakers, and
> > seem to see the issue at different times.
> >
> > The problem starts with:
> >
> > ospfd[6960]: recv_db_description: neighbor ID x.x.x.x: seq num mismatch,
> > bad flags
>
> The neighbor sent a db desc with the master flag set differently than what
> this ospfd instance recorded before for that particular neighbor.
>
> See 2nd last item on page 100 of RFC 2328:
> https://tools.ietf.org/html/rfc2328#page-100
>
> > ospfd[30114]: lsa_check: bad age
> >
> > And these just then continue, until we restart ospfd, and the problem
> > appears to go away.
>
> Is the neighbor also OpenBSD ospfd or something else?
>
> >
> > We are running some old routers on 5.8 and some new on 6.4. We appreciate
> > that we need to upgrade the 5.8 routers but we are keen to stabalise things
> > first.
> >
> > Having looked at the source, we can see the line generating the message:
> >
> > case NBR_STA_FULL:
> > if (dd_hdr.bits & OSPF_DBD_I ||
> > !(dd_hdr.bits & OSPF_DBD_MS) == !nbr->dd_master) {
> > log_warnx("recv_db_description: neighbor ID %s: "......
> >
> > Could anyone explain the scenario in which this would be expected, so we
> > can see how to resolve the issue.
>
> Please share a pcap file with the OSPF packets. With this we can better
> understand how this happens and where to look for a bug.
>
> >
> > We run some of our routers under VMware, could some sort of OS pause cause
> > this?
>
> Maybe if the router is not getting all OSPF packets because of this.
>
> Remi
