dhcp on IOS 12.2(29); how to set option 1

Unanswered Question
Nov 25th, 2007

I want to configure the client sub-mask to be when allocating a DHCP IP address from a network with a mask of This seems to be option 1, according to all docs, and the syntax should be quite simple "option 1 hex FF:FF:FF:FF". However, IOS hiccups, saying "DHCP, no raw value option 1". What is that all about? I don't know what "raw value" is or what the alternatives are. I've gone through every reference site that I can think of, and am still in the dark. Any clues as to how to achieve the goal?

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didyap Mon, 12/03/2007 - 08:42

Raw value is the value you have given after the "hex" word in the command for option 1. If you want to configure a raw DHCP option, you can figure out the right option format and configure the value correctly. For example if you want to give IP then its hex will be 010a.90dd.06, where

01 enc

0a 10

90 144

dd 221

06 06

mikegirou Mon, 12/03/2007 - 08:57

thanks, that's what I thought I was doing with the hex pattern of all F's (I tried 'ffff.ffff' as well as the string shown). However, I see that you start your string with '01', which you describe as 'enc'. What's that all about? The rest of the encoding is easy enough, so maybe the problem is my failure to understand '01' == 'enc'


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