DHCP string issue on Cisco 3560

Unanswered Question
Jan 17th, 2009
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I am experiencing a strange issue with the DHCP feature on the Cisco 3560 switch ( IOS 12.2(46) ).

If we reboot the Cisco 3560 switch DHCP Option 176 ascii string will be get added to another double colon. Hence Avaya IP Phones fails to register, as they don't know the Call Server IP address. So we need to reconfigure the DHCP option 176 string again after every reboot of the Cisco 3560 switch.

Before reboot switch configuration,

ip dhcp pool vlan100

network x.x.x.0

default-router x.x.x.x

domain-name example.com

dns-server x.x.x.x

netbios-name-server x.x.x.x

option 176 ascii "MCIPADD=x.x.x.x,TFTPSRVR=x.x.x.x,MCPORT=1719,L2Q=1"

after reboot,

option 176 ascii ""MCIPADD=x.x.x.x,TFTPSRVR=x.x.x.x,MCPORT=1719,L2Q=1""

Anybody faced the same issue ? Is it a software bug ?


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glen.grant Sat, 01/17/2009 - 03:38
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If thats what happening then yes I would get the tac involved , it could be a software issue . You would really be better off having a separate dhcp server to handle that stuff if you are using ip phones.


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