Re: socket in use

Steve,

This is from the IBM Infocenter page for the 'setsockopt()' API call,
under "usage notes":

    6. When a TCP connection is closed for a socket using the AF_INET
       address family, the port associated with that connection is not
       made available until twice the Maximum Segment Life (MSL) time in
       seconds has passed. The MSL time is approximately 2 minutes. The
       SO_REUSEADDR option allows a bind() to succeed when requesting a
       port that is being held during this time frame.
       This can be especially useful if a server is abruptly ended and
       restarted. 

You can read the whole thing online at:

http://publib.boulder.ibm.com/pubs/html/as400/v4r5/ic2924/info/apis/ssocko.htm


Sincerely,

Scott Klement
Mayor Of The Socket People


On Wed, 25 Jul 2001, Steve Richter wrote:

> Socket people,
> 
> I am getting an intermitent "socket in use" error in my as400 socket server
> pgm as I test my win95 to as400 socket code.
> 
> Even though the shutdown( ) and close( ) functions run without error, the
> next time I run my pgm, a "socket in use" error occurs on the Bind( ) stmt.
> And NetStat shows my prev use of the socket still in a listen state on the
> socket.
> 
> By using SetSockOpt( ), I think I have solved the problem. But varying the
> use of shutdown( ) and close( ) also reduced the frequency of the in use
> condition.
> 
> My question: Why does the correct use of shutdown( ) and close( ) not always
> free the socket?
> 
> Is there some timeout value that can be set?
> 
> Also, is there an api equivalent of NetStat?  When my pgm gets an "in use"
> return code, can it find out what job is using the socket?
> 
> And,  Can my pgm forcefully free up a socket that it knows is not really in
> use?
> 
> 
> Thanks,
> 
> Steve Richter
> 

+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---