Hi, I experiencing a strange difference between localhost and 127.0.0.1. In Pharo I do: (ZnServer startDefaultOn: 4444) onRequestRespond: [ :request | ZnResponse ok: (ZnEntity text: 'hello') ] In bash: $ lsof -Pi | grep Pharo Pharo 2718 luc 7u IPv4 0x1e64a2e9381f409b 0t0 TCP *:4444 (LISTEN) I perfectly listen on port 4444 from all interfaces * $ curl http://127.0.0.1:4444 hello $ curl http://localhost:4444 curl: (7) Failed to connect to localhost port 4444: Connection refused *<- why ?* localhost is correctly resolved on my mac $ ping localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.044 ms I tested with other programs than Zinc to open listening sockets and it works. Any idea? #Luc