Posts Tagged With ‘firewall’

1. Analyzing a failed TLS connection

   Summary This post demonstrates how to correlate two or more trace files to analyze a broken connection. We identify the root cause and gather information about the network topology. Tracefiles are available at http://www.packet-foo.com/blog/TLS/Skype.zip We assume that the reader is familiar with TCP basics like session setup, retransmissions, window size etc.

2. Firewall trouble

   A few days ago my connection(s) to the computing center suddenly degraded, meaning that I suddenly could not contact some of my servers anymore or only after waiting for sometimes minutes, while others worked fine. I checked the Icinga monitoring system and saw that everything was fine, except the firewall, which seemed to have a […]