MTU question

What type of wireless equipment are you running?  How many of them do you have.  Check wireless routers etc.

If you have a large network it helps to diagram out each segment.

There is no wireless.  My network is pretty small.

First, how did you determine that there was a device with the MTU setting of 1300?
1300 is a default setting for any system with Cisco VPn client software..

It was determined by a cisco engineer.  I have a client using my vpn concentrator to access a reporting server.  They have an app that forces them to only use 1500.  They cannot negotiate.  When they try to access my reporting server over a Lan-to-Lan tunnel (pix to 3030 concentrator) the software times out.  I opened a case up with tac and was told after they viewed all of the logs that i have a device in my network that is forcing the mtu to 1300.  it didn't make a whole lot of sense to me and I don't know how to determine the mtu of all of the devices on my network.  (without a lot of manual labor)

You only need to look at the client, the server, and all devices between the client and the server.

Client -->PIX-->router<---internet--->router-->VPN3030-->switch?-->server

Each interface of each device in between has the ability to be manually adjusted to specify an MTU

I've looked at all of those.  There is still an issue.  According to the engineer at tac there could still be a device other than those causing this.  I'm just looking for an automated way to determine the MTU of the devices on my network.