DHCP Database full problem on 3750

Unanswered Question
Nov 3rd, 2011
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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

   domain-name mydomain.com

   dns-server 4.4.4.4 8.8.8.8

   default-router x.x.70.1

   lease 8


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.


Thanks,

Ron

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drstokes76 Tue, 11/29/2011 - 07:20
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I too came across the same issue, I'm running the same version


I had a DHCP pool which should have allowed 30 addresses, but was saying that I'd excluded 240 addresses.  I also had to delete the pool and start again.  Quick fix but annoying.


Thanks

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