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How to reset network connection with ndd

dictum9
Super Advisor

How to reset network connection with ndd

I ftp and also sftp / scp to another machine and the connection is intermittent. it sometimes works and sometimes does not. I do not get any errors, it just hangs.

 

The source is 11.31 machine, the target is a mainframe.

 

I have engaged the network people and all they can do is verify there are timeouts.

Is there an ndd setting I can reset to  to do a TCP/IP reset?

2 REPLIES
Steven Schweda
Honored Contributor

Re: How to reset network connection with ndd

> The source is 11.31 machine, the target is a mainframe.

   Do you mean "client" and "server"?

> Is there an ndd setting I can reset to to do a TCP/IP reset?

   I've never touched "ndd", so I know nothing, but, from what I've
read, "ndd" sets network parameters -- it doesn't cause any action to
occur.  Thus, I would not expect it to be able to "do a TCP/IP reset",
whatever that means.

   If these problems occur only when dealing with a particular remote
system, then I'd guess that the problem lies with that particular remote
system (or a part of the network specific to it), not with the HP-UX
system.

   If a file transfer gets hung, then I'd expect that killing the local
client program would reset everything which could be reset from the
HP-UX (client) side.

> [...] I do not get any errors, it just hangs.

    And what information is available from the other (server) side?

   When a file transfer gets hung, what happens to other communication
("ping", another file transfer, SSH, Telnet, ...) between these two
systems?

> [...] there are timeouts.

   Not a very detailed description.  I'd expect a timeout to be an
error, different from a hang, but that would depend on what, exactly,
times out.

Laurent Menase
Honored Contributor

Re: How to reset network connection with ndd

Are you looking for ndd -set /dev/tcp tcp_discon_by_addr ?

- works, but not supported

2 ways 
ndd -get /dev/tcp tcp_status 
...
e00000075a066b80 127.000.000.001 3fb97ff1 3fb97ff1 00008000 00008000 3fba8965 3fba8963 00008000 00500 16384 [ea0a,17] TCP_ESTABLISHED
..

# ndd -set /dev/tcp tcp_discon 0xe00000075a066b80

or

# netstat -an |grep 23
tcp 0 0 10.10.16.138.23 10.10.16.113.49842 ESTABLISHED
ndd -set /dev/tcp tcp_discon_by_addr $(printf "%02x%02x%02x%02x%04x%02x%02x%02x%02x%04" 10 10 16 138 23 10 10 16 113 49842 )