Yes. When both BGP peers are up and running, the Mikrotiks directly
connected to the Ciscos both have a default route from their
respective Ciscos. Its only when connection A goes down, and
therefore, we lose that default, that things go nuts. When this
happens, the Cisco on connection B is still redistributing its default
route. This is evidenced by the fact that all of the V3 and V2.9
routers in the network switch to connection B's default route, as one
would expect. All of the V4 and V5 routers, however, just drop the
default from the routing table.
Craig
Quoting "[email protected]
(mailto:[email protected])" <[email protected]
(mailto:[email protected])>:
> Do the Mikrotiks connected to the BGP routers show they are getting
> the default route
> from the Cisco they are connected to?
>
> On Fri, Dec 9, 2011 at 3:50 PM, Craig Baird <[email protected]
(http://web.com)> wrote:
> > The Ciscos are receiving the default route via BGP from the
upstream. They
> > are redistributing it to OSPF via "default-information originate".
> >
> > No static defaults anywhere.
> >
> > Craig
> >
> >
> >
> > Quoting "[email protected]
(mailto:[email protected])" <[email protected]
(mailto:[email protected])>:
> >
> > > Are the Ciscos sending the default route via BGP or OSPF? If via BGP,
> > > make sure you have Redistribute Default Route set in OSPF. Make sure
> > > you don't have a static default route anywhere either.
> > >
> > > On Fri, Dec 9, 2011 at 3:21 PM, Craig Baird
<[email protected] (http://web.com)> wrote:
> > > >
> > > > I've got a very weird situation that has come up lately.
Wondering if
> > > > anyone has any ideas. I've got two connections out to the
Internet that
> > > > enter my network in two different locations. Upstream ISP
is the same on
> > > > both connections. We run BGP with them via two Cisco edge
routers. They
> > > > send us a default route, which I'm injecting into OSPF at
both locations.
> > > >
> > > > Now here's the weird part. If I lose BGP for connection A, every
> > > > Mikrotik
> > > > V4 or V5 box in my network loses its default route completely. In
> > > > contrast,
> > > > all my V3 or V2.9 (yes, I still have some of those) routers
install the
> > > > new
> > > > default route in the routing table, and off they go without
so much as a
> > > > blink. If I do a 'routing ospf lsa print', the LSA for the
new default
> > > > is
> > > > there. But it never gets installed in the routing table.
In order to
> > > > get
> > > > these V4 and V5 routers to pick up the default, all I have
to do is make
> > > > a
> > > > change to OSPF somewhere on the network. I can make that
change anywhere
> > > > on
> > > > the network. It doesn't have to be on one of the V4 or V5
routers. Any
> > > > simple change will suddenly make these routers pick up the
new default.
> > > >
> > > > To make it even stranger, this problem doesn't happen in
reverse. If I
> > > > lose
> > > > BGP for connection B, the default route for connection A
propagates to
> > > > all
> > > > routers in the network and everything is fine.
> > > >
> > > > I've been googling on this and found a few similar posts on
the MT forum,
> > > > but nothing where MT has ever acknowledged that it's a bug. It sure
> > > > looks
> > > > like one to me though, since it only affects V4 and V5
routers. I have a
> > > > difficult time believing that such a bug could exist
through an entire
> > > > release's life cycle and well into the next without being fixed.
> > > >
> > > > Does anyone have any insight on this?
> > > >
> > > > Craig
> > > >
> > > >
> > > > _______________________________________________
> > > > Mikrotik mailing list
> > > > [email protected] (mailto:[email protected])
> > > > http://www.butchevans.com/mailman/listinfo/mikrotik
> > > >
> > > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik
> > > > RouterOS
> > > >
> > >
> > >
> > > _______________________________________________
> > > Mikrotik mailing list
> > > [email protected] (mailto:[email protected])
> > > http://www.butchevans.com/mailman/listinfo/mikrotik
> > >
> > > Visit http://blog.butchevans.com/ for tutorials related to Mikrotik
> > > RouterOS
> > >
> >
> >
> >
> > _______________________________________________
> > Mikrotik mailing list
> > [email protected] (mailto:[email protected])
> > http://www.butchevans.com/mailman/listinfo/mikrotik
> >
> > Visit http://blog.butchevans.com/ for tutorials related to
Mikrotik RouterOS
> _______________________________________________
> Mikrotik mailing list
> [email protected] (mailto:[email protected])
> http://www.butchevans.com/mailman/listinfo/mikrotik
>
> Visit http://blog.butchevans.com/ for tutorials related to
Mikrotik RouterOS
_______________________________________________
Mikrotik mailing list
[email protected] (mailto:[email protected])
http://www.butchevans.com/mailman/listinfo/mikrotik
Visit http://blog.butchevans.com/ for tutorials related to Mikrotik RouterOS
