Vendor options not being sent

Arno Lehmann al at
Wed Sep 15 19:28:27 UTC 2010


15.09.2010 15:33, Glenn Satchell wrote:
> On 09/15/10 22:52, Arno Lehmann wrote:
> The other possibility is that the size of the options are too big to fit 
> in the remaining space in dhcpd packet.

I avoided the octet-counting ntil now, but verified now... the UDP 
packets sent are 328 octets long now. Ethernet MTU is the typical 
1500, which should leave more than 1000 octets for further options... 
the client announces that it would accept up to 1472 octets in reply 
packets, which - no surprise here - is the maximum UDP packet size per 
ethernet frame. Counting my data lengths, I get much less than 200 
extra octets, so the whole stuff should easily fit into the replies.

> I remember reading about 
> trimming path lengths to minimise the size. The setting is option 
> dhcp-max-message-size <size>, although the examples I gave are from my 
> working config, so those sizes are ok.

As I do not specify that in the server's configuration, the client's 
suggested size should be used, and that is 1472. I don't think this is 
the cause of my trouble...



Arno Lehmann
IT-Service Lehmann
Sandstr. 6, 49080 Osnabrück

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