My home network has a Linux box running IPTables as it’s center point, and, since there are four networks, it has 4 NICs and 4 cables into the switch. I kept running into problems with the NICs (they would reorder depending on what flavor of Linux was installed), so I wanted to consolidate the...
Posts Tagged ‘ lan ’
Configuring Dedicated Trunks for the CSM
Did you catch the article on setting up fault tolerance on the CSM? In that article, I mentioned that Cisco recommends a dedicated trunk for the FT VLAN if you have two HA CSMs in two chassis. Discuss amongst yourselves while I drone on. Why should you set up a dedicated trunk for this...
Using CDP To Track Down Physical Connections
We have a location that’s a few blocks down from the main office here, and we were reviewing the circuit size to make sure it was sized properly. Since not one person knows what’s going on and the trending graphs gave us conflicting details, one of our network dudes took me down to the...
Using MAC Access-lists
We ran into this today, and, though I knew it existed, I never actually saw it in the wild. I’m talking about MAC access-lists. In the example setup, we have a DMZ off of a firewall that contains a whole mess of servers — email, web, ftp, etc. These should all be in the...
Back to Basics — CAM Table Population
At the office, we reprovision servers like it’s going out of style. It happens so often that my cabling documentation rarely matches what’s actually out in field, which is a pretty big problem when you’re trying to find to what switch port a server is connected. I finally relegated myself to asking for the...
Cheat Sheets from Packetlife.net
My friend Josh over at blindhog.net has found a collection of cheat sheet gems for the network dude(tte). There’s sheets on BGP, OSPF, Subnetting, QoS, connector types, and more. Check it out. Cheat Sheets – Packetlife.net Aaron ConawayI like to lean my head to the left, hit it with the palm of my right...
Storm Control
We run a large number of LANs all over the country that are “controlled” by the particular business unit. We manage the gear, but, since they have the money and have to pay for anything we do, they make the final decision on what gets put in. Sometimes that gets out of hand, as...
Getting Started with EtherChannel
In my professional life at some point, I came across someone who had a stack of Catalyst 2950 switches all trunked together with their Internet routers connected to the top of the stack. This was all well and good until they kept adding hosts to the “middle” of the stack, then they had all...
VTP and You
VLAN Trunk Protocol (VTP) is a little gem on Cisco switches that allows you configure VLANs in one place and have them appear on all of your switches. This is great for large enterprises with 8457839 switches all trunked together because who wants to configure the new VLAN for that one-off application on all...
DHCP on the ASA 5505
Let’s keep going with our example setup on the ASA 5505 and set up DHCP on this guy. You can set it up to either forward (relay) DHCP requests to a DHCP server somewhere or have it be the DHCP server. Let’s do it. To set up DHCP forwarding, you have to configure where...
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