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DHCP relay with Sophos UTM

Hello,

I bet this is very simple to answer, but I just cannot make it work.

I am creating VLANs for some servers, and the first time also doing DHCP from other network - should be simple enough - create a DHCP relay and that's it... or not?

In any case, in Sophos UTM, I created a DHCP relay for both interfaces pointing to the DC1 in Network1. Network2 is where the new server (call it Server1) resides.

Doing some basic network analysis via tcpdump, I can see that the Server1 sends a Discover, DC1 gets the Discover and makes an Offer, Server1 sees the offer, but that's it. The process repeats itself, Server1 starts the Discover yet again. There is no IP assigned.

It looks like Server1 is not going a Request.

Any ideas?

(EDIT: maybe important, the requests are coming from PXE boot in Hyper-V, and while the problem persists for PXE boot, it does work in windows - I installed windows in another network, then moved the VM, and it pulled the IP from DHCP)

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0 Alexander Busch over 4 years ago

Did you put interfaces of both networks in the corresponding field in the UTM?

BR

Alex

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0 Kosta88 over 4 years ago in reply to Alexander Busch

Yes, I did.

Seemingly, I got an half-answer on another forum.

The reason why PXE boot fails is because there is no IP Helper to forward the requests to WDS too - maybe you correct me?

There is no sense in using DHCP Options 66 and 67, because here one cannot differentiate between different boot images for different scenarios (besides, I did try to set it up, unsucessfully too).
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0 FormerMember over 4 years ago in reply to Kosta88

Hi Kosta88

Are there any DHCP options being requested? If yes, are those options being responded properly by the DC1 DHCP server?

Thanks,
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0 Kosta88 over 4 years ago in reply to FormerMember

Hello,

I am not sure if I can answer this correctly: I don't know where I would see DHCP options being requested.

But, I already dumped this idea, because not being able to choose and image, or better said, it doesn't know which bootloader to choose from.

I am better of by just installing the server in the same network as WDS, and then just moving it somewhere else if needed.
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