TCP & curl-loader question

[Gary F. <ga...@in...>]

Hello Robert,

I've run into a problem that seems unrelated to the curl-loader  
extensions I'm building. This occurs whenever I have two or more  
virtual clients running simultaneously. Here's what I see when I look  
at the TCP traffic with Wireshark:

Roughly half the clients proceed normally. The server sends the final  
response of the conversation, the client ACKs this, and then the  
client initiates a FIN-ACK and the server replies with FIN-ACK. That's  
it, and everyone's happy.

But with the rest of the clients, something happens in the middle of  
the conversation, before the client is ready to finish. The server  
replies to a client request, the client ACKs this reply, and then the  
server unexpectedly initiates a FIN-ACK. The client responds with two  
RST packets, but the server doesn't react, and the client times out.

Unfortunately I'm no TCP expert. Is this a server malfunction? Or  
perhaps this is normal server behavior, and the curl clients should  
handle the unexpected FIN-ACK differently? I don't know if you can  
shed any light on this, but I'd be grateful for any ideas.

I've included a tcpdump file (which you can view with Wireshark) and  
the .log file. (It's interesting that in the case of the  
malfunctioning clients, the final server reply is never logged,  
although it appears in the tcpdump.) I can send the .conf file as well  
if you want (but that might just be a distraction). The command line  
was $curl-loader -u -v -f genusers.conf. The same thing happens when I  
add the -r option.

Thanks,
Gary Fitts