Satoshi replied to Bohm’s connectivity issue the next day, advising him to forward port 8333 on his new router. He explained that without port forwarding, Bohm’s node could not receive incoming connections from other peers.
Satoshi noted that if nobody currently online could accept inbound connections, nodes would fail to connect to the network entirely — highlighting just how fragile the Bitcoin network was in mid-2009 with only a handful of active nodes accepting inbound connections.