Custom DHCP options per range within a pool
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We have two types of devices on a subnet; PCs and VoIP handsets.
We only want to advertise a handful of specific routes rather than setting the default gateway on the PCs (the default gateway is on a separate NIC).
I can set the specific routes OK by using DHCP option 121 under the 'Additional BOOTP/DHCP Options', and this works great for the Windows PCs.Our issue is that the VoIP handsets appear to ignore option 121 and only pay attention to the default gateway setting (DHCP option 3?). For the VoIP handsets, it is acceptable to set the default gateway.
So, effectively we want to be able to use DHCP option 3 for the VoIP handsets (This can be filtered by MAC address starting with XX:YY:ZZ), and DHCP option 121 for everything else.I thought that I'd be able to achieve this by adding two ranges to the DHCP pool; then on the range for the VoIP handsets set 'MAC allow' along with the DHCP option 3, and then for the second range set DHCP option 121.
It seems that it isn't possible to set individual 'MAC allow' and DHCP options on different ranges within a pool. Instead they appear to be configured for the entire pool only.
Have I missed something?
If this isn't possible from the web UI, would it be safe (albeit undesirable) to make manual changes to the underlying configuration file? Under what circumstances will this typically get overwritten? i.e. as long as I don't touch the DHCP server settings through the web interface, will the manual changes remain intact? -
You'd put the options for most clients on the main servers settings, and put the VoIP MAC prefix in the MAC Deny box there.
Then in the pool for the VoIP handsets, put their MAC in the MAC Allow box and use the VoIP-specific options you want on that pool.
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Thanks @jimp - I'm not sure how I missed that, it's obvious in hindsight.
DHCP is now working exactly as needed.
