[stunnel-users] Connection problems and TCP frame checksum errors
ttn at mbnet.fi
Sat Oct 21 11:11:39 CEST 2006
thanks for all your suggestions. They were really helpful
in bringing me to the solution of the problem.
> 1. "netstat -an" - to make sure stunnel is listening on the correct
> interface and port
This was OK.
> 2. does "lastcomm stunnel' show anything useful? If you don't use threads
> a new stunnel process starts with each connection.
This showed nothing useful.
> 3. just a guess but remove the socket entries in the config file - maybe
> they are causing a problem. I don't use them but maybe there is a
> good reason to use them.
The socket entries were there because they were in the original
config file which I edited for my purposes. They seemed ok to me
so I left them in my config when I began experimenting with stunnel.
Commenting them out didn't make any difference for this problem.
> 4. try connecting directly to the stunnel box (no router). does that
> always work
Maybe not always, but remarkably better!!!
> 5. maybe the NIC card is flaky
The card had worked just fine until then, so I didn't really
believe in this. I thought I'd save this for the last.
> 6. run "stunnel -version" to verify all is configured as you think.
Seems all right.
So what the heck could the problem be. It took me a long time to
figure out the answer. The fact that almost all connection attempts
succeeded when the router was left out of the picture would suggest
there was a problem with the router configurations. But no, the
router was correctly configured. Instead, the routing tables of the
linux work station were not right! That's a problem I've hardly ever
had to deal with (and therefore a subject I don't understand enough of)
so it took some experimenting to get the routing tables right. Now it
looks good. I still can't explain why the original routing tables
sometimes worked and sometimes didn't, but I'll study the subject :-)
More information about the stunnel-users