“We are all good. BGP established!”
That was the entire useful update after a long night of routers, firewalls, and provider emails.
The small network had just received its own autonomous-system number from ARIN. That meant it could establish BGP sessions with more than one provider and advertise its own route instead of treating each circuit as an isolated connection.
The approval was only the paperwork. The network still had to work. My job was to turn the new number into a working route without breaking the circuits already carrying traffic.
One provider terminated on a router, while BGP ran from firewalls behind it. The session therefore needed multihop configured correctly. A setting of one hop was never going to reach a peer that sat several hops away.
The thread went back and forth through the evening. Was the provider side correct? Was the customer equipment correct? Which address should peer with which? Were the route filters ready to prevent one provider's routes from leaking into the other?
The final problem came down to changing the multihop value from one to three.
That sounds small because it was small. It was also the difference between a configured network and a working one.
Once the session came up, the larger design could finally do what it was meant to do. The company had its own network identity, two upstream paths, and a cleaner way to handle failure than waiting for somebody to manually move everything.
The message went out at the end of the night from my phone.
BGP established. Go home.