[j-nsp] Odd issue with logical-system

[Eric Van Tol]

Hi all,
Since I've now run into this issue a second time, I figured I'd reach out to the community to see if anyone else has experienced this. I'm working on a pair of MX960s, running 13.3R6.5. 

I have a pair of logical systems (LS1, LS2) configured in each MX960 (MX1, MX2) and both MXs are directly attached and in production with no other issues. Each logical system is configured to IBGP peer with each MX, but not each other. 

My problem is that LS1 is unable to bring up a BGP session with MX2. I've disabled all lo0 filters to ensure that it's not a filtering problem. Routing is working properly, as I can ping each MX from each LS and vice versa. If I do a 'monitor traffic interface' on MX2 and on LS1, I can see the MX sending a TCP SYN and it's received on LS1, but it's just dropped silently. I can also see an originating TCP session in the 'show system connections' output on LS1, but no packets are being seen leaving LS1. I also see absolutely nothing when I enable traceoptions on the peer in LS1 and with MX2 attempting to contact LS1.

Anyone else seen this? I don't see any PRs related this in 13.3R6, either.

Thanks in advance,
evt