[Dnsmasq-discuss] dhcp-option=252: DHCP request for unsupported hardware type (0) recieved on eth1

Simon Kelley simon at thekelleys.org.uk
Mon Jul 18 21:08:04 BST 2005

Stanley Jaddoe wrote:
> Hi,
> After upgrading Debian woody to sarge, I'm trying to set up dnsmasq to replace 
> the dhcp3 daemon.
> My old (working) dhcpd.conf contains:
> # wpad proxy config
> option wpad code 252 = text;
> option wpad "http://server/proxy.pac";
> This enables browsers such as IE and Konqueror to automatically detect proxy 
> settings using WPAD and DHCP.
> In dnsmasq, I use:
> # set WPAD proxy location
> dhcp-option=252,http://server/proxy.pac

That looks fine.

> (full config below)
> However, the clients are unable get the value of dhcp option 252 (wpad). 
> dnsmasq reports the following in daemon.log on the server:
> Jul 17 14:41:24 P1 dnsmasq[1718]: DHCP request for unsupported hardware type 
> (0) recieved on eth1

This seems to indicate that the "htype" field in the DHCP message is set 
to zero. This indicates the type of network that the request originates 
from, and should be one, for ethernet.

> What should I do to make WPAD via DHCP work in dnsmasq?

Do you know how the browsers are getting the information from the DHCP 
server? Is it being passed on by the DHCP client, or are the browsers 
sending a DHCPINFORM request themselves? You could do some packet 
capture using ethereal and send me the results.

My guess is that the browser is sending a DHCPINFORM request, and 
getting the value of the htype field wrong. This works with some DHCP 
servers "by accident" but not with dnsmasq. (I just checked the source 
of ISC dhcpd 2.x , because it's on my diskand it seems to be the case 

Alternatively, htype=0 might be a valid wildcard value, but I can't find 
any reference to that in a Google search.

The ultimate solution will probably be to make htype=0 a valid case in 
dnsmasq, but it would be good to understand what's going on first.



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