I'm assuming he means he blocked it from triggering the interesting traffic. If he blocks tcp completely across the port, then how's he going to run BGP to get routing information? You'll have to block BGP out of both ends, though, and make it not only traffic sourced from 179, but also destined to 179. One end of any given BGP connection is always on an ephermal port.
No, we're all just trying to figure out what you mean by "flapping." Is the link dialing, and you don't want it to? Or is the link shutting down, and you don't want it to? Or is the link staying up, and the BGP session is failing and coming back?
only run OSPF between R1 and R2, we can use "ip ospf demand-circuit" to avoid the ISDN flapping, because the Hello was suppressed.
But, if run BGP between R1 and R2, and BGP send "keep alive" every 60 seconds, and the ISDN will be up because the "keep alive", after that, ISDN will be down because "no traffic",(idle-timeout 30), and ISDN will be up again, because the next "keep alive" coming and will be down again without traffic.
so I think, no way to solve the problem, cisco does not provide command like "ip bgp demand-circuit".
I have the question because I was thinking in a large enterprise network, run IGP and BGP, the ISDN just for backup and no flapping for IGP. but maybe the BGP will keep the ISDN flapping and we have to pay for the flapping.
You can make the BGP keepalive packets not initiate the ISDN call by denying them in an access-list referenced by the 'dialer-list' command. However, that would require you to use some other type of routing to get the intial user data to initiate the ISDN call. A floating static route may work ...
Can you share more information about your architecture?
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...