Any routing marks involved? Any mangle or firewall rules which would
match this customer and not others?
When you're saying "traceroute stops at", is that the site giving the
last reply?
What if you specify different source IP's on your traceroute from the
NOC? Maybe tower A is missing one route, but not others.
One other thing....I had a couple of anomalies go away when I switched
OSPF interfaces from broadcast to point-to-point mode. I thought the
only difference was the OSFP messages are sent unicast, but a few goofy
things stopped happening when I did that.
------ Original Message ------
From: "Justin Marshall" <just...@pdmnet.net>
To: "af@afmug.com" <af@afmug.com>
Sent: 3/31/2017 12:55:43 PM
Subject: [AFMUG] Strange OSPF problem
Hi,
I have an odd situation with OSPF.
There are 2 towers (Tower A and Tower B) and a NOC involved that feeds
both towers.
Tower A is directly connected to the NOC via Mikrotik Backhaul. Tower
B is directly connected to the NOC via Fiber.
Tower B is connected to Tower A via Fiber.
When tower A is running straight off the NOC (via Mikrotik Backhaul)
everything works as it should.
We are trying to make a switchover to have Tower A run off Tower B so
it will be a Fiber connection all the way to Tower A (through tower B)
and eliminate the Mikrotik Backhaul.
When I change cost on the OSPF interfaces to make this happen, all
customers work as they should and following the normal path to/from the
Internet as expected. However, for one of the customers on Tower A,
traceroutes to that one customer stop at Tower A (through tower B) from
the NOC. Traceroutes towards the NOC, from the customer stops at Tower
B.
All customers are on the same subnet.
I can directly ping the customer in question from both Tower B and
Tower A (and the traffic is taking the correct path), but not from the
NOC. From the NOC all traffic stops at Tower B
The only real difference for the customer that is not working is they
are using a Sonic Wall, and the other customers have Mikrotik routers
behind the CPE's. We have tried elimating the sonc wall, and replacing
it with a laptop for testing, and the traffic flow failed in the same
way.
Tried all kinds of things and we are quite stumped.
Anyone have any suggestions?
Thanks,
Justin
just...@pdmnet.net
