Dear Hamish, thanks for your help. Here's what "dig localhost MX" gives to me : # dig localhost MX ; <<>> DiG 9.2.4 <<>> localhost MX ;; global options: printcmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29075 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0 ;; QUESTION SECTION: ;localhost. IN MX ;; AUTHORITY SECTION: localhost. 604800 IN SOA localhost. root.localhost. 1 604800 86400 2419200 604800 ;; Query time: 54 msec ;; SERVER: 195.238.2.21#53(195.238.2.21) ;; WHEN: Tue Jan 18 19:05:26 2005 ;; MSG SIZE rcvd: 68 My internet provider DNS is 195.238.2.21 The "dig localhost" telles me that localhost is 127.0.0.1 And finally, here's my "telnet localhost 25" result : # telnet localhost 25 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 suse.local ESMTP Postfix I don't understand what's the problem Laurent Renard