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Conference turris::digital_unix

Title:DIGITAL UNIX(FORMERLY KNOWN AS DEC OSF/1)
Notice:Welcome to the Digital UNIX Conference
Moderator:SMURF::DENHAM
Created:Thu Mar 16 1995
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:10068
Total number of notes:35879

9166.0. "Dynamic port allocation problem" by SMAUG::GANTYALA () Thu Mar 13 1997 12:24

Hi,

The problem is related to the dynamic assignment of TCP port number. When a
client wishes to connect to a server listening on a well-known port number
108. On the client side system choose the port number (may be in the range
of 1025 to 5000) to have a unique socket connection. When client issues a
socket call connect() to the server, it fails with errno 48 i.e. EADDRINUSE. 
This means that client gets the port number, which was already assigned to its
earlier connection in use. 

Is there any mechanism to increase the range of dynamic port number allocation?.

-Ramesh
T.RTitleUserPersonal
Name		DateLines
9166.1SMAUG::GANTYALAThu Mar 13 1997 12:3211
Hi,

I forgot to mention two things:

1. I am using Digital Unix version 4.0a 

2. The connect() fails just after 3970 connects to well known server port. 
   This means the range of available ports for dynamic assignment: 
          5000 - 1024 = 3976. 

-Ramesh
9166.2kernel variable ipport_userreservedSMURF::DUSTINThu Mar 13 1997 14:3310
    You can dbx -k /vmunix and increase ipport_userreserved from
    5000 to some larger number.  The port number is limited to
    16 bits, so don't exceed 64K here..
    
    This was supposed to be added to the sysconfigtab support in V4.0A but
    was inadvertently missed.  We will add sysconfig support in the next
    release.
    
    John