[j-nsp] Help: Learning routes from same ASN, cisco vs juniper

OBrien, Will ObrienH at missouri.edu
Tue Sep 10 13:28:52 EDT 2013


I've found an interesting issue and I wanted to get some thoughts before talking to JTAC about it.


I have a few of MX480s.  In the past, I've advertised a dedicated /24 from my lab to my providers upstream.
That /24 was never learned by my primary MX.

The issue comes down to either the MX or the Cisco filtering routes that are from the same ASN.  It's been a couple of years since I ran across this and I can't remember who was at fault.


This behavior is biting my with regard to my DR site.


At my DR, I have a SRX with say ASN 1234. It's advertising a /24.

At my primary site, I also use ASN1234. I do not receive the /24 via BGP.

So, either the Cisco (7600 I think) isn't advertising the route to me because it's from my ASN - OR - The MX is filtering it because it's from my ASN and coming in on a eBGP link.


If it's the MX, I'm certain I can write an import filter, but I'm having an issue hunting down syntax on that.
If it's the Cisco, then I can yell at the provider to have them open a TAC case. 



Like I said, I ran across this a few years ago, but can't remember who was at fault. I could build a multi-hop neighbor relationship to get around this, but surely there's a simpler solution...


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