Re: Die, Sockets! Die!

[roemer@informatik.uni-frankfurt.de]

> Observe the following:
> 
> Active TCP connections
> Proto  Recv-Q Send-Q Local-Address        Foreign-Address      State
> TCP         0      0 203.4.148.180:telnet 203.2.122.69:1834    ESTABLISHED    
> TCP         0     33 203.4.148.180:1098   203.4.148.1:telnet   FINWAIT1       
> TCP         0     17 203.4.148.180:1078   192.107.41.6:telnet  LASTACK        
> TCP         0      0 203.4.148.180:1064   203.4.148.1:smtp     FINWAIT2       
> TCP         0      0 203.4.148.180:1051   138.74.0.10:8888     ESTABLISHED    
> TCP         0      0 203.4.148.180:1028   203.4.148.1:telnet   FINWAIT2       
> 
> This is my net connection in the process of dying. The two TCP connections
> that have the data in the Send-Queue will never close. When this happens
> my connection slowly decreases in response, getting slower and slower and
> slower.

Well, those two connection having still data in their send queues have parially
closed down (FINWAIT1 and LASTACK states...). The connection in FINWAIT state
is trying to get the pending data over the line, possibly retransmitting it
over and over jamming the SLIP output queue if the timeout is too small.

Please switch on debugging info (alt+f1) and look for messages like:

sl?: output queue full

and send me the output of

ifstats sl0

or whatever your interface name is (the interesting part in the output is
the `packets dropped while output queue full').


Kay.
--
Kay Roemer              roemer@informatik.uni-frankfurt.de
"If I ever meet ..."    http://www.uni-frankfurt.de/~roemer/
"... myself I'll hit myself so hard I won't know who hit me" (Zaphod)