I have a Java application (let's call it AppX) running on the following software/hardware stack:

- Server1 (old x86 hardware, Intel P3 CPU)
- SuSE Linux Enterprise Server 8
- MySQL
- Java Run-time Environment 1.4
- Apache Tomcat (used as webserver and servlet container)
- AppX (webapp using https connection)

AppX is happily running on Server1 with no problems.

*I need to move AppX to Server2 (IBM ThinkPad T42 hardware)*

I have loaded Server2 with the exact software stack. Everything runs fine except for one problem; while using AppX, the web browser sporadically reports losing the secure connection (I use IE 6 from a W2K machine in my LAN). I have tried this on several machines and they all lose connection. This does not have happen when trying to reproduce running AppX on Server1.

I have narrowed this problem down to the network level, as Tomcat is requesting/sending information as expected.

Since this is quite a tricky one to solve straight off, my question is more around how to debug this;

- what tools can I use (on SLES 8) to debug my network problems?
- is there a tool to see the data going in and out of the ethernet network card on Server2?
- are there any log files associated with information going through the network card?

Thanks in advance.
- Newbie.

- tcpdump and/or Ethereal (ettercap would be a good thing to use too, but you're not really set up for that, and it might only make this particular situation harder to diagnose)
- see above
- Only if you have a firewall set up to log, and that's not going to go into the detail the other tools will