Switching

Fiber optics and UDLD

RenĂ© Jorissen on October 20, 2008 0 Comments • Tags: #aggressive #bpdu #detection #fiber #forwarding #learning #link #listening #mode #normal #optics #stp #udld #unidirectional

UDLD (Unidirectional Link Detection) is a protocol to help prevent forwarding loops in switched networks. A fiber cable is build from two separate fibers (transmit and receive), where one of the two fiber could fail, which would result in a switch port not able to receive or send traffic. This scenario could result in some … Read More

Configuration Example, Firewalling

PIX Failover not working

RenĂ© Jorissen on June 18, 2008 0 Comments • Tags: #error #failover #normal #not #pix #waiting #working

Today I received the question why a PIX failover configuration wasn’t working. The customer accidentally disconnected the power cable from the primary PIX firewall. The secondary PIX firewall became the active one, but multiple DMZ segments weren’t working anymore. After rebooting the PIX firewall and making that the primary one again, the DMZ segments were … Read More