Problems with applications through Alteon switch....

[oyvind_s3]

Hello,

I am posting this because we have a problem where I am working. I would be grateful if you could give me some possible solutions to this problem.

Our systems are running as following:

The users connect to our applications through Alteon equipment (consisting of two parts, i.e. an SSL Accelerator and a Load Balancer) and a web server with IBM HTTP server v6.1 installed. (Alteon translates the HTTPS traffic into HTTP and forwards it to the web server. The Load Balancer function is not in use, and is practically a standard switch). A WebSphere plug-in module in the IBM HTTP server takes care of the routing to the different WebSphere Application Servers.

Several times in the last couples of months, we have experienced some problems where the users have not been able to access the applications. The URL is returning a 404-error, and this has happened at irregular times. When the error occurs, it looks like the plug-in module stops routing the requests, and we get HTTP 404 error messages. In other words, the requests never arrive at the application server. We suspect that a reason to our problem might be that the Alteon switch or the web server (or both) somehow have been overloaded, but we are not sure how this has happened. We are considering other possible solutions as well, e.g. that it might have something to do with the network or that something in the plug-in file has caused these problems. Whenever the 404 has occurred, our temporary solution has been to restart the Alteon switch. It does not work just to restart the IBM HTTP server. When the error occurs, we still manage to access the applications through http directly, by using the application server IP address and the application server port. However, this is only a workaround, and not a solution to the problem.

The last time we had these problems, I tested all the URLs in our system to check whether all of the applications were impossible to access, or if we managed to access some of them. The conclusion was that some of the applications actually were accessible, even if the majority of them was not. I also checked whether there were some patterns in which applications that worked and which did not, but I was not able to find any.

Any clues on what might be the cause of our problems, and how we might solve them?

Thanks!

[Tripredacus]

The 404 Error is a response that comes from the webserver, so its definately not a problem of the clients not being able to communicate with the server. If the clients couldn't communicate, they would get a different message, and not a return code at all.

Your webserver should be logging all codes. Check the instances of 404 responses and see what URLs or resources were trying to be accessed.