Answer strings

The servers normally answer with specific answer strings:

HTTP (Port 80): HTTP answers, when everything is OK, with „HTTP/1.0 200 OK“ or „HTTP/1.1 200 OK“.

SMTP (Port 25): answers with „220“. An exchange server returns „220 ovsrvexch.ovag.de Microsoft ESMTP MAIL Service Version: 5.0.2195.5329 ready at  Fri 23 Jan 2004 19:16:08 +0100“

FTP (Port 21): returns „220“, too.

POP3 (Port 110): answers with the string „+OK“. An exchange server e.g. answers with “+OK Microsoft Exchange 2000 POP3 server version 6.0.6249.0 (ovsrvexch.ovag.de) ready. “

IMAP4 (Port 143): answers with the string „* OK“.

NNTP (Port 119): answers with the string „200“.An Exchange server e.g. returns “200 NNTP Service 5.00.0984 Version: 5.0.2195.5329 Posting Allowed” .

Telnet (Port 23): that’s a little more complicated because telnet doesn’t return clear text. A Cisco router or switch returns

         

A Sun Solaris server answers with

         

and a Linux-Server with

         

These characters can be found by typing the following combination:

y with two dots above: <Alt> 0 2 5 5
u with acent (roof): <Alt> 0 2 5 1
y with acent (from left below to right above): <Alt> 0 2 5 3

To monitor the Sun Solaris you can use