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Hello, This is the problem: 1 webserver running postfix to send vbulletin email notifications. The problem is I need to monitor when it's up and when it's not, so.. configured ...
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  1. #1
    Just Joined!
    Join Date
    Aug 2009
    Posts
    8

    Can't telnet port 25


    Hello,

    This is the problem:

    1 webserver running postfix to send vbulletin email notifications. The problem is I need to monitor when it's up and when it's not, so.. configured nagios but it doesn't seem to be responding to network requests.

    This is what I got:


    Code:
    ~/home/nagios/libexec/check_smtp -H 11.11.11.110 -p 25
    Connection refused
    SMTP CRITICAL - 0.006 sec. response time|time=0.006173s;;;0.000000
    So, started diggin a little bit and this is what I found:

    Service is up and running:

    Code:
    ~service postfix status
    master (pid 2386) is running...

    Code:
    ~fuser -v 25/tcp
    
                         USER        PID ACCESS COMMAND
    25/tcp:              root       2386 F.... master
                         postfix    2451 F.... smtpd
                         postfix    2462 F.... smtpd
    Code:
    ~nmap -p 25 localhost
    
    Starting Nmap 4.11  at 2011-06-29 12:01 CDT
    Interesting ports on localhost localdomain (127.0.0.1):
    PORT   STATE SERVICE
    25/tcp open  smtp
    
    Nmap finished: 1 IP address (1 host up) scanned in 0.014 seconds

    Firewall is down:


    Code:
    ~csf -x
    [  OK  ] lfd:[  OK  ]
    Flushing chain `INPUT'
    Flushing chain `FORWARD'
    Flushing chain `OUTPUT'
    Flushing chain `DSHIELD'
    Flushing chain `INVALID'
    Flushing chain `INVDROP'
    Flushing chain `LOCALINPUT'
    Flushing chain `LOCALOUTPUT'
    Flushing chain `LOGDROPIN'
    Flushing chain `LOGDROPOUT'
    Flushing chain `SPAMHAUS'
    Deleting chain `DSHIELD'
    Deleting chain `INVALID'
    Deleting chain `INVDROP'
    Deleting chain `LOCALINPUT'
    Deleting chain `LOCALOUTPUT'
    Deleting chain `LOGDROPIN'
    Deleting chain `LOGDROPOUT'
    Deleting chain `SPAMHAUS'
    csf and lfd have been disabled
    
    ~iptables -F
    You have new mail in /var/spool/mail/root
    And still can not reach port 25 telnetting from outside:

    Code:
    ~telnet 11.11.11.110 25
    Trying 11.11.11.110...
    telnet: connect to address 11.11.11.110: Connection refused
    telnet: Unable to connect to remote host: Connection refused
    You have new mail in /var/spool/mail/root
    From inside the server, it works great:

    Code:
    ~telnet localhost 25
    Trying 127.0.0.1...
    Connected to localhost.localdomain (127.0.0.1).
    Escape character is '^]'.
    220 monitoring.server.com ESMTP Postfix
    Any idea what am I missing?

    Thanks a lot!

  2. #2
    Trusted Penguin
    Join Date
    May 2011
    Posts
    4,353
    Just a guess, do you have tcp_wrappers configured? check /etc/hosts.deny

  3. #3
    Just Joined!
    Join Date
    Jun 2010
    Location
    CA
    Posts
    20
    your system may be refusing telnet requests

    telnet has security issues and should be avoided

    try:

    ssh -P 25 <user>@11.11.11.110

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