Had a problem with a 3750 this morning not handing out DHCP addresses. The following is a sanitized config of what the switch is using -
ip dhcp excluded-address x.x.70.1 x.x.70.19
ip dhcp excluded-address x.x.70.210 x.x.70.254
ip dhcp pool PC
network x.x.70.0 255.255.255.0
dns-server 184.108.40.206 220.127.116.11
The IOS installed on the switch is c3750-ipbasek9-mz.122-55.SE1.bin. What got my attention was that the sh ip dhcp pool PC showed 180 addresses being excluded. In doing the math from the dhcp excluded addresses, only 64 should be excluded.
My next step was to remove the second dhcp excluded-address line above. Doing a clear ip dhcp binding * started letting the DHCP service hand out addresses but the sh ip dhcp pool PC stil showed 180 addresses excluded.
It finally took removing the dhcp pool and putting it back in to drop the number of excluded addresses down to a value that matches the first excluded-address line. Didnt see a dhcp bug in the bug database that would explain this. Anyone else seen this ?
I tried re-entering the second excluded-address line from above and saw the number of excluded addresses rise as expected. When I negated the line, the number of excluded addresses dropped back to its previous value.