This is just a quick post to highlight a quirk I found with the Sonicwall DHCP server (built-in DHCP server in Sonicwall firewalls).<\/p>\n
I had an issue at a customer this past weekend where we had Cisco Access Points sitting behind a Cisco wireless controller and Cisco switch that pull their IP address from a Sonicwall firewall\u2019s DHCP server. We have reservations set up for each AP in the Sonicwall DHCP scope (each AP actually exists as a single entry scope as that is how Sonicwall handles DHC reservations; this is quite different from how DHCP reservations are handled in Windows) and the AP\u2019s would not pull their address after a prolonged network shutdown. I tried all sorts of things thinking that the problem had something to do with the Cisco controller but I did reboot the Sonicwall a couple of times, with no luck.<\/p>\n
After some messing about I dropped in a small dynamic DHCP scope on the subnet that the AP\u2019s are on and, BOOM! each AP pulled an address! Weird. I then dropped the dynamic scope and cycled the Sonicwall DHCP service which made no difference, AP\u2019s still did not pull their assigned addresses. On a whim I disabled all of the AP reservations then enabled just one, the assigned AP suddenly woke up and pulled its proper IP address. I enabled the rest of the reservations and all of the other AP\u2019s came back online with the correct addresses. Double weird.<\/p>\n
So, lesson learned. Cycling the Sonicwall and even cycling the DHCP service didn\u2019t \u201cwake up\u201d the static assignments but the individual disable\/enable did. If you hit a similar problem with Sonicwall DHCP reservations then this trick might help.<\/p>\n","protected":false},"excerpt":{"rendered":"