DHCP and DNS in routed network
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@johnpoz
so I have a question around DHCP for remote networks.
Why this feature has not been implemented yet with pfsense? are there any challenges ?
This is quite a common feature (when used with DHCP relay/IP helper) and to me it's a bit absurd that pfsense has to have an interface in the network so it can provide leases.Cheers!
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@Ethereal Something else would have to relay.
DHCP is basically the device asking “can anyone give me an address?” If there were two DHCP servers on a network with different settings, either may answer first.
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@SteveITS the relay is always done by the router of the network where the host asking for a lease, sits. These frames are L2 and don't go outside the broadcast domain.
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@Ethereal ok but in this scenario that’s not pfSense, correct? If the request is forwarded to pfSense how does pfSense know for what other network it should answer?
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@Ethereal pfsense does not support setting a scope for a non directly connected network maybe with the dhcpd that is coming they will that function?
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@SteveITS said in DHCP and DNS in routed network:
If the request is forwarded to pfSense how does pfSense know for what other network it should answer?
If pfSense did support this common feature, the relay sees the broadcast, sends a directed packet to the DHCP server including subnet information. The DHCP server responds with the lease information. The relay then responds with a broadcast to the original requester with the DHCP lease information. Works great in large networks.
Maybe the rumors of a change in DHCP server for pfSense will add this feature. -
@AndyRH I'm glad to see that there are many people out there asking for this feature to be implemented.
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I understand the request now. In a very quick search I found this 7 year old thread saying it doesn't work in Kea but maybe they have added it since.
https://lists.isc.org/mailman/htdig/kea-users/2016-December/000707.html
ref: Replace ISC DHCP server with Kea: https://redmine.pfsense.org/issues/6960
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@Ethereal said in DHCP and DNS in routed network:
many people
Define many? If you mean a few here and there as many - ok ;) hehehe
Most networks that get to the stage that they are routing downstream run their own dhcpd, and not off their edge router..
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If you use the Customer Service complaint theory, only a low percentage of people will complain, most just go somewhere else.
In the last few months I have seen 3 or 4 posts in some way related to DHCP relay. So 3 times some number that just do something else. That total has to be more than a few dozen. Enough to warrant adding the feature, maybe. If relay is a feature of KEA (I have found no evidence it is) then it would be wise to implement it.
In a lab environment relay would be nice so it can be used for practice.
I am more after the feature to add a reservation in the range, which appears to be a feature. It just makes it easier for me and I do not have IP address OCD so I am cool with "random" reservations. -
@johnpoz hahahaha yeah, well in my defense there are a few posts on this forum around this feature. People (like me) are a bit surprised that this is not supported and in the same time a bit disapointed, since it's quite a basic feature.
In the same time, you're not wrong about the dedicated DHCP server.
Myself I have the scopes configured on my 3750x switch, however would love to have them configured on the pfsense box. I love the gui, I can't help it.
