Trunks and VLANs and Firewalls, Oh my. (Part 3)
Posted 08-07-2008 at 09:26 PM by Bob_McMillen
Now that VLANs and phone commands are set up and the trunking commands are ready to tie the switches together, we are ready to make this work.
I first started with the core switches which were Cisco 3750's in a cluster of three. After inputting the commands the workstations started to come on line along with the phones.
But there was an entire section of servers we couldn't get to come online. We found out that those servers were hanging off a layer 2 switch. Now that complicates things. You can't trunk the two together because thats a layer 3 command. Layer two switches only memorize the MAC (or hardware) address of a network card. It doesn't route like layer 3 devices.
In order to fix this we decided to remove the portfast command which can cause a routing loop when connected to a switch. Now the servers started working great. They worked all night and into the next morning until the layer 2 switch crashed after a reboot of the core switches. It took out almost all of my configurations. The first night's work for us lasted until midnight. On day two we were on our way to another long day.
We showed up around 8 AM on a Saturday and got to work. I had to re input all the commands on the switches and we replaced the layer 2 switch with another 3750 layer 3 switch.
Now we had to connect the switches in the very large warehouse. The company keeps track of their stock by using wireless scanners. The WAPs are connected to switches in the warehouse on power poles rough 25 feet in the air. A scissor lift raises us up to these switches where we had to reboot all of them. They worked on the reboot but we could only get the workstations to come up. These were Cisco 500 switches and we couldn't tell how they were configured. So we had to get back up on the scissor lift and connect a hyperterminal cable each one to see how they are setup so can fix them properly. One problem though: The scissor lift ran out of battery power and they only had one.
On to tomorrow and the next segment of our story.
I first started with the core switches which were Cisco 3750's in a cluster of three. After inputting the commands the workstations started to come on line along with the phones.
But there was an entire section of servers we couldn't get to come online. We found out that those servers were hanging off a layer 2 switch. Now that complicates things. You can't trunk the two together because thats a layer 3 command. Layer two switches only memorize the MAC (or hardware) address of a network card. It doesn't route like layer 3 devices.
In order to fix this we decided to remove the portfast command which can cause a routing loop when connected to a switch. Now the servers started working great. They worked all night and into the next morning until the layer 2 switch crashed after a reboot of the core switches. It took out almost all of my configurations. The first night's work for us lasted until midnight. On day two we were on our way to another long day.
We showed up around 8 AM on a Saturday and got to work. I had to re input all the commands on the switches and we replaced the layer 2 switch with another 3750 layer 3 switch.
Now we had to connect the switches in the very large warehouse. The company keeps track of their stock by using wireless scanners. The WAPs are connected to switches in the warehouse on power poles rough 25 feet in the air. A scissor lift raises us up to these switches where we had to reboot all of them. They worked on the reboot but we could only get the workstations to come up. These were Cisco 500 switches and we couldn't tell how they were configured. So we had to get back up on the scissor lift and connect a hyperterminal cable each one to see how they are setup so can fix them properly. One problem though: The scissor lift ran out of battery power and they only had one.
On to tomorrow and the next segment of our story.
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