I thought I'd share an event that just occurred, partially because I like making fun of myself but also because it's educational.
At one of our remote locations we have some users who periodically use video conferencing for training purposes. Last week, our LAN group decided to move that entire floor to a different VLAN. Not remembering the video conferencing equipment, I told them it would be fine to do that. This morning, a class gathered at that location and then attempted to connect to the video conference. You can guess what happened... Because they had an IP address from a different LAN--and the wrong default gateway--they could not connect. I knew from past studies that there was a Cisco Jedi trick that would solve this and even though I had configured it before I just couldn't remember how to do it. Thankfully, for my purposes a single line did the trick. On the subinterface going to the new VLAN, I simply added "ip mobile arp". In conjunction with proxy arp this allows users to migrate from one directly attached LAN to another. The router will add /32 host routes into the routing table as it discovers these users. As soon as I entered the command I could ping the video conferencing unit from my desktop here at headquarters. The video unit still has the wrong default gateway but the router handles that problem using proxy arp. This doesn't make up for the fact that we weren't very thorough in our migration plans. In fact, we didn't really have any plans since we thought it would be so simple. However, in a pinch this worked out quite well and I was able to diffuse the situation before someone blew out an artery. :-) Regards, John Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=39770&t=39770 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
