[Dnsmasq-discuss] Possible bug setting dhcp-option 17

Michael Welle m.welle at gmx.net
Mon Oct 10 21:36:19 BST 2005


Simon Kelley wrote:
> Michael Welle wrote:
> > no, this is the only option. Plus the default options set by
> > dnsmasq. 
> > 
> > 
> >
> > You mean option 57 max msg size? 
> Yep.
> Hm, the current packet size seems to
> > be 328 byte. How is it calculated? 
> It's set to be the minimum size mandated by the DHCP spec, which is 576 
> bytes, HOWEVER, if BOOTP is in use rather than DHCP, then the "vendor 
> oprions" field is only 64 bytes, according to to RFC 951, so the maximum 
> packet size is reduced to 328 (rest of packet + 64 byte option
> field)

> Are you using BOOTP? If so, then that explains things. Can you use DHCP 
> instead? (BYW the option 57 stuff is not specified for BOOTP, so that 
> wouldn't help.)
Sorry, I should have mentioned that. I guess my problem is solved now
(and I should have a closer look at the relevant rfc). Maybe you can
write a warning into the logs in such a case? I find it a little bit 
confusing to set an option in the conf file and see it silently
disappearing on its way to the client ;). 

Thank you

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