Port Used to Communicate Between Two HPUX Servers - HP UX

This is a discussion on Port Used to Communicate Between Two HPUX Servers - HP UX ; Hi, I am installing some SAP software on a couple of HP-UX v11.11 servers. As part of this installation (EP6.0 Web Dispatcher, for those familiar with SAP), I need to specify a port for communication between the two HP-UX servers. ...

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  1. Port Used to Communicate Between Two HPUX Servers

    Hi,

    I am installing some SAP software on a couple of HP-UX v11.11
    servers.

    As part of this installation (EP6.0 Web Dispatcher, for those
    familiar with SAP), I need to specify a port for communication
    between the two HP-UX servers. There is no firewall or anything
    else (To the best of my knowledge) hindering communication
    between the servers.

    I chose port 8081 (SAP's suggested default), but the functionality
    did not work. SAP's logs indicated communication issues between
    the two HP-UX servers.

    I tried other port numbers, but the same issue occured.

    In the SAP documentation, they suggest trying (From host1)
    'telnet ' to check whether the port is
    valid.

    I tried 5 or 6 ports, but telnet always failed with the
    message 'telnet: Unable to connect to remote host: Connection
    refused'. Yet, the command 'telnet ' works.

    Where can I get more information as to which ports may be
    valid for communication between the servers? I checked
    'netstat' and '/etc/services', but I am having a hard time
    determining this.


    Thanks,
    BASIS Consultant


  2. Re: Port Used to Communicate Between Two HPUX Servers

    basis_consultant@hotmail.com wrote:
    > I am installing some SAP software on a couple of HP-UX v11.11
    > servers.


    > As part of this installation (EP6.0 Web Dispatcher, for those
    > familiar with SAP), I need to specify a port for communication
    > between the two HP-UX servers. There is no firewall or anything
    > else (To the best of my knowledge) hindering communication
    > between the servers.


    > I chose port 8081 (SAP's suggested default), but the functionality
    > did not work. SAP's logs indicated communication issues between
    > the two HP-UX servers.


    > I tried other port numbers, but the same issue occured.


    > In the SAP documentation, they suggest trying (From host1)
    > 'telnet ' to check whether the port is
    > valid.


    > I tried 5 or 6 ports, but telnet always failed with the
    > message 'telnet: Unable to connect to remote host: Connection
    > refused'. Yet, the command 'telnet ' works.


    Unless there is a TCP endpoint in the LISTEN state (netstat -an) on
    the remote system, where the endpoint is bound to the value to
    which you are trying to connect, the error message you get from telnet
    is expected.

    So, check netstat -an | grep LISTEN on the remote system first.

    Did you start the SAP software on the remote side?

    rick jones
    --
    a wide gulf separates "what if" from "if only"
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

  3. Re: Port Used to Communicate Between Two HPUX Servers

    Hi Rick,

    Thanks for the response. I made a mistake in the original
    description; The problem is not the communication between the
    servers, but that the server containing the Web Dispatcher
    cannot access a port needed for the functionality to work:

    [Thr 6] *** WARNING => Connection request from (0/0/0) to host:
    , service: 8881 failed (NIECONN_REFUSED)
    {00010002} [icxxconn_mt.c 2123].

    Thus, it seems like the issue is that the SAP configuration
    expects HP-UX to use a specific port number (Mentioned in
    an SAP config file) and that HPUX cannot use that port.

    Port does not show up on 'netstat -an'.

    Thanks,
    BASIS Consultant

    Rick Jones wrote:
    > basis_consultant@hotmail.com wrote:
    > > I am installing some SAP software on a couple of HP-UX v11.11
    > > servers.

    >
    > > As part of this installation (EP6.0 Web Dispatcher, for those
    > > familiar with SAP), I need to specify a port for communication
    > > between the two HP-UX servers. There is no firewall or anything
    > > else (To the best of my knowledge) hindering communication
    > > between the servers.

    >
    > > I chose port 8081 (SAP's suggested default), but the functionality
    > > did not work. SAP's logs indicated communication issues between
    > > the two HP-UX servers.

    >
    > > I tried other port numbers, but the same issue occured.

    >
    > > In the SAP documentation, they suggest trying (From host1)
    > > 'telnet ' to check whether the port is
    > > valid.

    >
    > > I tried 5 or 6 ports, but telnet always failed with the
    > > message 'telnet: Unable to connect to remote host: Connection
    > > refused'. Yet, the command 'telnet ' works.

    >
    > Unless there is a TCP endpoint in the LISTEN state (netstat -an) on
    > the remote system, where the endpoint is bound to the value to
    > which you are trying to connect, the error message you get from telnet
    > is expected.
    >
    > So, check netstat -an | grep LISTEN on the remote system first.
    >
    > Did you start the SAP software on the remote side?
    >
    > rick jones
    > --
    > a wide gulf separates "what if" from "if only"
    > these opinions are mine, all mine; HP might not want them anyway...
    > feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...



  4. Re: Port Used to Communicate Between Two HPUX Servers

    basis_consultant@hotmail.com wrote:
    > Hi Rick,
    >
    > Thanks for the response. I made a mistake in the original
    > description; The problem is not the communication between the
    > servers, but that the server containing the Web Dispatcher
    > cannot access a port needed for the functionality to work:
    >
    > [Thr 6] *** WARNING => Connection request from (0/0/0) to host:
    > , service: 8881 failed (NIECONN_REFUSED)
    > {00010002} [icxxconn_mt.c 2123].
    >
    > Thus, it seems like the issue is that the SAP configuration
    > expects HP-UX to use a specific port number (Mentioned in
    > an SAP config file) and that HPUX cannot use that port.
    >
    > Port does not show up on 'netstat -an'.
    >
    > Thanks,
    > BASIS Consultant
    >
    > Rick Jones wrote:
    >
    >>basis_consultant@hotmail.com wrote:
    >>
    >>>I am installing some SAP software on a couple of HP-UX v11.11
    >>>servers.

    >>
    >>>As part of this installation (EP6.0 Web Dispatcher, for those
    >>>familiar with SAP), I need to specify a port for communication
    >>>between the two HP-UX servers. There is no firewall or anything
    >>>else (To the best of my knowledge) hindering communication
    >>>between the servers.

    >>
    >>>I chose port 8081 (SAP's suggested default), but the functionality
    >>>did not work. SAP's logs indicated communication issues between
    >>>the two HP-UX servers.

    >>
    >>>I tried other port numbers, but the same issue occured.

    >>
    >>>In the SAP documentation, they suggest trying (From host1)
    >>>'telnet ' to check whether the port is
    >>>valid.

    >>
    >>>I tried 5 or 6 ports, but telnet always failed with the
    >>>message 'telnet: Unable to connect to remote host: Connection
    >>>refused'. Yet, the command 'telnet ' works.

    >>
    >>Unless there is a TCP endpoint in the LISTEN state (netstat -an) on
    >>the remote system, where the endpoint is bound to the value to
    >>which you are trying to connect, the error message you get from telnet
    >>is expected.
    >>
    >>So, check netstat -an | grep LISTEN on the remote system first.
    >>
    >>Did you start the SAP software on the remote side?
    >>
    >>rick jones
    >>--
    >>a wide gulf separates "what if" from "if only"
    >>these opinions are mine, all mine; HP might not want them anyway...
    >>feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

    >
    >

    Is the port number/UDP-TCP defined in the /etc/services file? And
    perhaps it also need to be defined in /etc/inetd.conf as the application
    that needs to run when the port is opened ( I'm not familiar w/ SAP )

  5. Re: Port Used to Communicate Between Two HPUX Servers

    basis_consultant@hotmail.com wrote:
    > Hi Rick,


    > Thanks for the response. I made a mistake in the original
    > description; The problem is not the communication between the
    > servers, but that the server containing the Web Dispatcher cannot
    > access a port needed for the functionality to work:


    > [Thr 6] *** WARNING => Connection request from (0/0/0) to host:
    > , service: 8881 failed (NIECONN_REFUSED)
    > {00010002} [icxxconn_mt.c 2123].


    > Thus, it seems like the issue is that the SAP configuration expects
    > HP-UX to use a specific port number (Mentioned in an SAP config
    > file) and that HPUX cannot use that port.


    > Port does not show up on 'netstat -an'.


    If the port does not show-up in netstat -an output then either the
    thing that was supposed to create a listen endpoint on that port is
    not running, or its attempts to create the listen endpoint failed.

    One one machine, or the other, start a tcpdump trace with the snaplen
    set to oh 128 bytes. Feel free to use a filter expression for just
    that port number:

    tcpdump -i -s 128 -w /tmp/trace.raw

    then try the connection, then stop the tcpdump trace and process it:

    tcpdump -r /tmp/trace.raw -x (or -X) Find the TCP SYNchronize segment
    - it will be the one with the 'S' flag set. You should then see a TCP
    ReSeT segment ('R') in response. Working backwards from the last of
    the hex output for that segment, find the corresponding ASCII
    character (man ascii) and you will get the error message that HP-UX
    puts into its RST segments by default. I suspect it will say
    something like "no listener" or somesuch.

    rick jones
    --
    portable adj, code that compiles under more than one compiler
    these opinions are mine, all mine; HP might not want them anyway...
    feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

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