eBGP Implementation

[Marcm19921]

Lets's say my router is sitting behind a firewall, obviously I would have to use the ebgp-multihop command to establish the tcp session with my ISP. Would I simply inform my ISP of the number of hops necessary in order to form the BGP session? 

I have no personal experience using eBGP, I've only done it within my lab. So I'm just looking for some advise on practical real world implementation. 

[balaji.bandi]

yes, you need to have a multihop config , if that is not directly connected.

Also, note - on FW  make sure you open the required Port for BGP peering.

[Marcm19921]

I'm aware of that. My question is simply would you let your ISP know that they need to increase the TTL?

[Reza Sharifi]

I'm aware of that. My question is simply would you let your ISP know that they need to increase the TTL?

Yes, you need to let them know so, they can add the multihop command to your connection/peering.

HTH

[balaji.bandi]

Obviously right, if you are configuring multihop, same on other side also multihop.

"if that is not directly connected" multihop config required both sides.

[Richard Burts]

If the topology is like this ISP <--> your firewall <==> your router The ISP will know the IP of the firewall that it connects to. In addition to informing the ISP of the number of hops you need to communicate to them what is the IP address of your router and what AS number you will be using.

[MHM Cisco World]

if you can do traceroute to ISP, 
if the ASA appear then use ebgp-multihop number as hop number appear 
if the ASA is not appear then use ebgp-multihop number as hop number appear + 1

remember each hop will reduce ttl by 1.