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

Simon Kelley simon at thekelleys.org.uk
Mon Oct 10 21:22:30 BST 2005

Michael Welle wrote:

> no, this is the only option. Plus the default options set by
> dnsmasq. 
> You mean option 57 max msg size? 

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.)



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