SMTP Relay 설정 및 EXPN, VRFY 명령어 활성 테스트

- Relay 설정 확인

[root@test]~# nc -vv X.X.X.X 25

220 XX.example.com ESMTP Postfix (Ubuntu)

EHLO

..............

mail from:<test@example.com>

250 2.1.0 Ok

rcpt to:<receive@example.com>

250 2.1.5 Ok

dat

354 End data with <CR><LF>.<CR><LF>

This is Spam test.

.

250 2.0.0 Ok: queued as xxx

quit

221 2.0.0 Bye

- EXPN, VRFY 테스트

$ telnet X.X.X.X 25

Trying X.X.X.X...

Connected to X.X.X.X.

Escape character is '^]'.

220 smtp-relay.exanple.com ESMTP Postfix

VRTY root

502 5.5.2 Error: command not recognized

EXPN root

502 5.5.2 Error: command not recognized

quit

221 2.0.0 Bye

Connection closed by foreign host.