VLAN

Cisco switchport mode access vs switchport access vlan

What’s the difference between “switchport mode access” and “switchport access vlan xx”? First of all, both commands are required to set the switch to an access port. switch(config-if)# switchport mode access This above command disables DTP – Dynamic Trunking Protocol…


SNMP Packet discards on Nortel/Avaya ERS 5510/5520

Recently I’ve setup a monitoring tool called Intermapper to monitor the Nortel switches I have at work. The tool polls the SNMP traffic information from the switches, and also picks up some basic error notifications received on it’s ports. On…



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Cisco IOS HSRP Problem – More than one Active router

HSRP is commonly used as a router failover mechanism, where one router in the group is active and all other group members are in standby. A standby router will take over as the active router when connectivity to the active…


Cisco ASA Failover Tips and misc.

When setting up a Cisco ASA failover pair, try to follow the following rules & tips: Do not use a crossover Ethernet cable or a fiber-optic patch cable to directly connect the two failover LAN interfaces if the firewalls are…


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How to configure VLANs in Linux

This link from the Redhat knowledge base talks all about it. Here’s the list of steps and pointers I had to go through. 1. Make sure that the 8021q module is loaded modprobe 8021q 2. This step is important as…