SANS – SEC401 Security Essentials Day – 4

Security 401.4 – Secure Communications Day 4 was Crypto day. Brutal for those who are first timers and definitely not a breeze even if you’re a seasoned sysadmin. How many professionals even know the difference between Asymmetric and Symmetric encryption?…

Troubleshooting VPN slowness – A look at MTU

Problem: Troubleshooting vpn slowness and packet retransmits could be a puzzling task, especially when it’s over an IPsec tunnel. Last week I had the opportunity to troubleshoot a problem with slow website loading times on a webserver across the link….

Troubleshooting Cisco PIX/ASA site to site IPsec VPN

A site to site IPsec VPN consists of two phases; Phase 1 – IKE exchange and Phase2 – Establishing the ipsec tunnels. It is important to figure out which part of the negotiation the VPN is failing at. However, before…