Update:
I am prepending my AS 3 times to the un-preferred ISP.
Both ISP's are my peers. The un-preferred ISP claims
the see my advertisement yet they do not add it to
their routing table (suggests filtering??). They claim
all the filtering they are doing is based on the
networks I told them over the phone that I was using
with that AS.
Philip
To answer your originial question: it is not "normal" to filter routers with
the same AS prepended 3 times. However if the ISP chose such a policy they
could do that.
On this subject:
When they say "do not add it to their routing table" do you know if they mean
the BGP table or the IP table?
i.e. if the ISP in question does a "sh ip bgp route <your prefix>" does it
show in the list. Yet when they do a "sh ip route <your prefix>" it does not.
If so then your ISP will be preferring a different route.
Are you certain that the prefix filters this ISP is using - well sounds like
they are using - are the same as the prefixes you are announcing? It could be
that the prefix list is misconfigured.
I am prepending my AS 3 times to the un-preferred ISP.
Both ISP's are my peers.
Ok...I just wanted to be sure you weren't prepending their ASN in which
case loop detection would stop them from accepting your routes.
The un-preferred ISP claims the see my advertisement yet they do not add
it to their routing table (suggests filtering??). They claim all the
Does the un-preferred ISP actually have no route back to you, or just not
the one you sent to them? Depending on how things are setup, they may
prefer your preferred ISP for reaching you. If you want "un-preferred
ISP" to reach you directly, but still be "un-preferred", you may want to
see if they have communities you can tag your advertisement with that
would cause them to prepend your routes when propogating them to their
peers.
Philip Lavine wrote:
Update:
I am prepending my AS 3 times to the un-preferred ISP.
Both ISP's are my peers. The un-preferred ISP claims
the see my advertisement yet they do not add it to
their routing table (suggests filtering??). They claim
all the filtering they are doing is based on the
networks I told them over the phone that I was using
with that AS.
I have heard of providers who filter on AS path, and filter in such a way that more than N prepends (for varying values of N) causes the route(s) to be rejected. This could potentially be your problem. If they do soft-reconfig in on their customer sessions, they may see the route but filter it out.
pt