[Dnsmasq-discuss] IP address based on switch port number (option 82)
simon at thekelleys.org.uk
Sat Feb 13 09:30:13 GMT 2010
Ignacio.Bravo at belden.com wrote:
> Hello List,
> I try without success to assign always the same IP (or range) per switch
> port (no matter the mac address, only matters the port at which the
> client is connected)
> To do this I use switches with dhcp relay option 82 activated. So
> telling, any discover getting to dnsmasq includes circuit-id and remote-id
> I dont understand the usage of dhcp-circuitid and dhcp-remoteid
> commands, may you please post me an example?
> I tried the following at dnsmasq.conf:
> Would this suffice? I suppose not as it does not work. (Hex values got
> from wireshark so they should be ok)
You're certainly on the right lines. As few things to check:
Don't use very old dnsmasq releases, there have been bugs in the
cricuit-id matching code, so you need 2.44 or later.
turn on dhcp logging with --log-dhcp that will tell you if the tag is
I suspect that you might be matching too much data: your hex looks very
much like it includes the sub-option and length bytes as the first two.
dnsmasq understands the sub-option format and will not need to see that.
Could you post a packet capture here, or send direct to me?
> Any help is appreciatted!
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