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In one of our Redhat AS 5.5 server, port number 1551 is taken, so software that depends on it is failing to start up. Output of "netstat -a -n | ...
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  1. #1
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    Mystery port


    In one of our Redhat AS 5.5 server,
    port number 1551 is taken, so software that depends on it is failing to start up.
    Output of "netstat -a -n | grep 1551" is shown below:


    tcp 0 0 192.168.222.218:54927 192.168.222.217:1551 TIME_WAIT
    unix 3 [ ] STREAM CONNECTED 3405715519


    However, output of "lsof" (ran as root) is showing no process holding these ports. Both commands shown below return nothing:


    /usr/sbin/lsof -i -n -P -M | grep 1551
    /usr/sbin/lsof -i -n -P -M | grep 54927


    How can we find out which process is holding this mystery port 1551? Thank you in advance.

  2. #2
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    as root, try this:
    Code:
     netstat -a -n -v -e -e -p 2>&1|egrep ':1551|:54927|Active|Proto'

  3. #3
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    Thank you so much for help. It returned following output.
    "PID/Program name" column is blank,
    and "State" is TIME_WAIT.
    What does this mean? There is no process on this port?
    What is going on and what should we do to free this port?
    Thank you so much again.


    Code:
    Proto Recv-Q Send-Q Local Address               Foreign Address             State       User       Inode      PID/Program name
    tcp        0      0 192.168.222.218:30014       192.168.222.217:1551        TIME_WAIT   0          0          -
    tcp        0      0 192.168.222.218:34710       192.168.222.217:1533        TIME_WAIT   0          0          -

  4. #4
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    I realize that 192.168.222.217:1551 is a different server
    and 192.168.222.218:30014 is the server where I can't start program trying to take over port 1551.
    Why would we have problem starting program to use port 1551? I'm perplexed.

  5. #5
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    Quote Originally Posted by robert7329 View Post
    "PID/Program name" column is blank,
    did you run the command as root?

  6. #6
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    Yes, I ran it as root

  7. #7
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    Quote Originally Posted by robert7329 View Post
    I realize that 192.168.222.217:1551 is a different server
    and 192.168.222.218:30014 is the server where I can't start program trying to take over port 1551.
    Why would we have problem starting program to use port 1551?
    you are trying to run a program on the local machine (192.168.222.218) and it wants to bind to port 1551? that does seem strange. can you share details about this error?

    also, here are some other things you can try (though they may return no new info):

    ss
    Code:
    ss -aep
    nmap
    Code:
    nmap -n localhost -p 1-65535
    you might need to get tcpdump going and start sniffing the traffic on your network device. maybe there is something in the packets that will help determine the source.

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