Test webserver with telnet
Telnet is a raw connection. This commandline tool could be used to debug different types of server services. Using telnet allows you to send anything untranslated, and see exactly what comes back.
Post describes how to use telnet for unusual purposes.
Port 21
How to login and execute commands on ftp server:
$ telnet ip.add.re.ss 21 Trying ip.add.re.ss... Connected to ip.add.re.ss. Escape character is '^]'. 220 ProFTPD 1.3.1 Server ready. user your_ftp_user 331 Password required for riverplantationcc pass your_ftp_password 230 User your_ftp_user logged in help 214-The following commands are recognized (* =>'s unimplemented): 214-CWD XCWD CDUP XCUP SMNT* QUIT PORT PASV 214-EPRT EPSV ALLO* RNFR RNTO DELE MDTM RMD 214-XRMD MKD XMKD PWD XPWD SIZE SYST HELP 214-NOOP FEAT OPTS AUTH CCC* CONF* ENC* MIC* 214-PBSZ PROT TYPE STRU MODE RETR STOR STOU 214-APPE REST ABOR USER PASS ACCT* REIN* LIST 214-NLST STAT SITE quit 221 Goodbye.
Port 25
How to send an email:
$ telnet ip.add.re.ss 25 Trying ip.add.re.ss... Connected to ip.add.re.ss. Escape character is '^]'. 220 localhost ESMTP Postfix (Ubuntu/GNU) HELO domain.tld 250 localhost MAIL FROM: root 250 2.1.0 Ok RCPT TO: <your@email_addre.ss> 250 2.1.5 Ok DATA 354 End data with . Subject: Email from ip.add.re.ss From: ip.add.re.ss Test data . 250 2.0.0 Ok: queued as 7C3F68464C1 quit 221 2.0.0 Bye
Port 80
How to retrieve a webpage:
telnet domain.tld 80 Trying ip.add.re.ss... Connected to domain.tld. Escape character is '^]'. HEAD / HTTP/1.1 Host: domain.tld HTTP/1.1 200 OK Date: Thu, 12 Nov 2009 10:41:18 GMT Server: Apache Last-Modified: Wed, 01 Apr 2009 15:02:13 GMT ETag: "b8c6a-73-4667f99bca740" Accept-Ranges: bytes Content-Length: 115 Vary: Accept-Encoding,User-Agent Content-Type: text/html
Port 110
How to check email account for new messages:
$ telnet domain.tld 110 Trying ip.add.re.ss... Connected to domain.tld. +OK Hello There user your_pop3_user +OK Password required. pass your_pop3_password +OK Logged in. stat +OK a b quit +OK goodbye
Port 143
How to login to a IMAP server:
telnet domain.tld 143 Trying ip.add.re.ss... Connected to domain.tld. Escape character is '^]'. * OK Dovecot ready. a login email@addre.ss your_password e a OK Logged in. a CAPABILITY * CAPABILITY IMAP4rev1 SASL-IR SORT THREAD=REFERENCES MULTIAPPEND UNSELECT LITERAL+ IDLE CHILDREN NAMESPACE LOGIN-REFERRALS AUTH=PLAIN AUTH=LOGIN a OK Capability completed. a logout * BYE Logging out a OK Logout completed.