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Server not responding to any external requests on SMTP port 25 RRS feed

  • Question

  • I set up a Windows Server 2008 Datacenter Edition and I got everything working on it except for my SMTP port 25, when I try to telnet into 127.0.0.1 25 it works fine, but when I try to use the public IP address it won't go through even if I try to telnet within the server using the public IP address.

     

    I got the Wireshark Capture but I couldn't figure out how to analyze the capture to see what is wrong.

     

    How should I handle this issue?

    Thursday, February 10, 2011 2:42 PM

Answers

  • Is your SMTP daemon (service) actually listening on the public interface?

    Do a "netstat -an" to verify.

    Make sure you don't have a firewall blocking it too of course.


    Matt W. CCNP, CCDA, CCNA-S, RHCT, MCSE, MCSA, MCP+I, A+
    • Marked as answer by TheSQLNewb Thursday, February 10, 2011 11:31 PM
    Thursday, February 10, 2011 3:21 PM
  • Hello Matt,

     

    I tried to do "netstat -an" but the list gets too long and I couldn't figure out how to go back to the top of the list to see port 25, I tried to do "netstat -a" which for the first couple of seconds shows "active connections" and I didn't see the 25 port on there (i saw port 26 and others).

     

    How can I debug this more?

    For future troubleshooting:

    netstat -an | more    = 1 screen of output at a time

    netstat -an > file.txt   = sends the output to a text file

    more file.txt   =   dumps it back to the console...


    Matt W. CCNP, CCDA, CCNA-S, RHCT, MCSE, MCSA, MCP+I, A+
    • Marked as answer by TheSQLNewb Friday, February 11, 2011 2:05 PM
    Friday, February 11, 2011 1:48 PM

All replies

  • Is your SMTP daemon (service) actually listening on the public interface?

    Do a "netstat -an" to verify.

    Make sure you don't have a firewall blocking it too of course.


    Matt W. CCNP, CCDA, CCNA-S, RHCT, MCSE, MCSA, MCP+I, A+
    • Marked as answer by TheSQLNewb Thursday, February 10, 2011 11:31 PM
    Thursday, February 10, 2011 3:21 PM
  • Hello Matt,

     

    I tried to do "netstat -an" but the list gets too long and I couldn't figure out how to go back to the top of the list to see port 25, I tried to do "netstat -a" which for the first couple of seconds shows "active connections" and I didn't see the 25 port on there (i saw port 26 and others).

     

    How can I debug this more?

    Thursday, February 10, 2011 3:41 PM
  • Hi dude

    the public ip address is on your server and is configured on a NIC.. security policies for public NICs on server 2008 are very very tight and most especially telnet into the public ip address of the server.. make sure your firewall has an exception for SMTP port 25.. but prior to this to do a simple test but very quick one since your server is connected directly to the public network.. disable the firewall on the NIC and do a quick test telnet <public ip> 25 and see if it works.. then switch the firewall back on again.. if it worked then u know u have to allow an exception on the firewall for port 25.. if it doesnt then could be some other problem we will need to verify.. and try doing the tests from another machine on the network as well to make sure and post the reusults you get :)


    tech-nique
    Thursday, February 10, 2011 4:06 PM
  • Thanks a lot, I now show 0.0.0.0:25 on the "netstat -an" as LISTENING, and I can telnet into the public IP address, the emails are not coming through though, where do I need to check for that information?
    Thursday, February 10, 2011 4:52 PM
  • I have both SMTP Server (which I use IIS 6.0 to manage) and hMailServer.  My domains and emails are set up on hMailServer, I am assuming that all the emails are trying to be processed through the SMTP Server (that is on IIS 6.0) and that's why they are not going through, can I disable the SMTP Server and just use hMailServer?

     

    To get everything working with hMailServer, do I need to have the SMTP Server running? and If so what do I need to do so that everything is processed through the hMailServer and not the one in IIS 6.0

    Thursday, February 10, 2011 5:06 PM
  • Hello Matt,

     

    I tried to do "netstat -an" but the list gets too long and I couldn't figure out how to go back to the top of the list to see port 25, I tried to do "netstat -a" which for the first couple of seconds shows "active connections" and I didn't see the 25 port on there (i saw port 26 and others).

     

    How can I debug this more?

    For future troubleshooting:

    netstat -an | more    = 1 screen of output at a time

    netstat -an > file.txt   = sends the output to a text file

    more file.txt   =   dumps it back to the console...


    Matt W. CCNP, CCDA, CCNA-S, RHCT, MCSE, MCSA, MCP+I, A+
    • Marked as answer by TheSQLNewb Friday, February 11, 2011 2:05 PM
    Friday, February 11, 2011 1:48 PM
  • Hello ,

    Did you solved your problem ?

    I've the same problem under Windows Server 2008  and hmailserver ...

    Can telnet 127.0.0.1 25 but cannot telnet 192.168.1.2 25

    Saturday, May 26, 2012 8:52 AM