Router analysis system

A computer-readable medium comprising computer-executable instructions, the computer executable instructions including:

• instructions for sending a first message from an applet to a server to test if an application layer gateway exists between the applet and the server;
• instructions for sending a second message from the applet to the server when a firewall allows an authentication challenge to be received at the applet;
• and
• instructions for sending a pinhole detection message to the server to indicate a detection of a pinhole when the applet stops receiving a particular type of messages from the server.

A system comprising:

• a router including an application layer gateway and a firewall;
• a client configured to:
• send a first message to a server through the application layer gateway to test whether the application layer gateway operates correctly,
• send an authentication reply in response to an authentication challenge when the firewall allows the authentication challenge to be received at the client, and
• send a pinhole detection message to the server to indicate a detection of a pinhole in the firewall;
• and
• the server configured to:
• receive the first message,
• send the authentication challenge to the client through the firewall to test if the firewall incorrectly prevents the authentication challenge from being delivered to the client, and
• send a plurality of messages to the client through the firewall to detect the pinhole.