Checking if a Port is Open

[Sean Knox]

The ssh is one option, and probably what I recommend. Another is 
installing NCSA on the remote box and allow passive checks to your 
Nagios server. Or, you can use snmp traps from the remote host to inform 
Nagios that port 25 is not accesible.

-sk

Carroll, Jim P [Contractor] wrote:

>One solution would be to have a host that you have access to which is out
>there in the 'outside world'.  This host would grant you, say, ssh access to
>it.  You could install the check_tcp plugin on that host, and kick it off
>from Nagios using check_by_ssh.  To wit:
>
>Nagios --> check_by_ssh --> check_tcp --> port 25 of Nagios host
>
>Food for thought.
>
>jc
>
>  
>
>>-----Original Message-----
>>From: Jake Colman [mailto:colman at ppllc.com]
>>Sent: Thursday, October 31, 2002 5:00 PM
>>To: nagios-users at lists.sourceforge.net
>>Subject: Re: [Nagios-users] Checking if a Port is Open
>>
>>
>>    
>>
>>>>>>>"SK" == Sean Knox <sean.knox at sbcglobal.net> writes:
>>>>>>>              
>>>>>>>
>>    SK> To check if a port is accessible from the outside 
>>world, just telnet
>>    SK> to the port. (i.e. telnet host 25)
>>
>>I run nagios on the same server that is running sendmail.  
>>The port is open
>>on my internal LAN so nagios will always be successful in 
>>monitoring and
>>connecting to the sendmail server.  My concern is with being 
>>able to monitor
>>that sendmail can be reached via port 25 (or that any server 
>>can be reached
>>via any arbitrary port) from the outside world.
>>
>>Is there a way to have nagios on my internal somehow run a 
>>check into port 25
>>but via the outside world?
>>
>>-- 
>>Jake Colman                     
>>
>>Principia Partners LLC                  Phone: (201) 209-2467
>>Harborside Financial Center               Fax: (201) 946-0320
>>902 Plaza Two                          E-mail: colman at ppllc.com
>>Jersey City, NJ 07311                  www.principiapartners.com
>>
>>
>>-------------------------------------------------------
>>This sf.net email is sponsored by: Influence the future 
>>of Java(TM) technology. Join the Java Community 
>>Process(SM) (JCP(SM)) program now. 
>>http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0004en
>>_______________________________________________
>>Nagios-users mailing list
>>Nagios-users at lists.sourceforge.net
>>https://lists.sourceforge.net/lists/listinfo/nagios-users
>>
>>    
>>
>
>
>-------------------------------------------------------
>This sf.net email is sponsored by: Influence the future 
>of Java(TM) technology. Join the Java Community 
>Process(SM) (JCP(SM)) program now. 
>http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0004en
>_______________________________________________
>Nagios-users mailing list
>Nagios-users at lists.sourceforge.net
>https://lists.sourceforge.net/lists/listinfo/nagios-users
>
>  
>



-------------------------------------------------------
This sf.net email is sponsored by: Influence the future 
of Java(TM) technology. Join the Java Community 
Process(SM) (JCP(SM)) program now. 
http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0004en