ˈt͡sɛːzaɐ̯: 
> Hm, sometime I still don't understand IPFS behavior at all. I can `ipfs swarm connect /ip4/80.208.230.208/tcp/4001/p2p/12D3KooWAivw38E5ohfpYo66FJTqYuWCsrBPPXjpHiCHh7fB5YYn`, but if I then try to ping the same address, it just timeouts.

Two reasons I can think of off the top of my head are:
1) If B is undialable (e.g. behind a NAT without UPnP) and A does `ipfs swarm connect B` it'll normally fail. However, if B has connected to A for some other reason (pretty common in testing scenarios) then A doing `ipfs swarm connect B` will succeed since they're already connected.
2) While B's firewall has been configured to allow libp2p connections through on port 4001 but rejects pings. Some networks reject pings to prevent network snooping of various sorts. You can notice similar behavior where sometimes websites will work just fine but doing `ping website.tld` will fail (e.g. usa.gov does this)