Hi,

Networking newbie here. Apologies in advance. I have a Draytek 2927 router which uses a Starlink dish as its main internet provision (with LTE failover, though this is irrelevant to this query I think). The Starlink dish has a DHCP server that (to the best of my knowledge) can't be disabled. I need reserved IP addresses for some devices on my network (which the Starlink doesn't support). If I turn DHCP on on the Draytek, devices still seem to get their IP addresses from the Starlink. I've had long exchanges with Draytek support to no avail.

I get that you never want two DHCP servers on the same network. But if I can't disable the Starlink, what are my options? I feel like I'm missing some fundamental simple solution here. The 2927 is part of an extensive wired network which included a few unmanaged 8 port switches.

I guess my basic question is: in a physically wired network that includes the 2927 and the Starlink, when a device is first connected it's just going to find the first DHCP server it can and get an IP address and subnet from there. It can't be limited to some subnet because it doesn't yet know anything about its place in the network, right? I think the topology I want is for the 2927 and Starlink to be one 'space' and the 2927, switches and WAPs to be another 'space' such that devices in the latter space are able to get their connection to the outside world via the 2927 (and thence Starlink) but otherwise can't 'see' the Starlink. (And I know you can dispense with the Starlink router, but the dish itself is a DHCP server, right?)

As I type this, I feel sure the answer is simple but I've now confused myself so much with LANs, VLANs, subnet masks etc. etc. that I've completely lost the plot! Any help or pointers would be very much appreciated.

The dish itself has a built in dhcp server. you can use the starlink provided router in addition to your own, or not. if you use the SL router, you get a double nat thing going, so not ideal. but some do as the dishy dhcp behaviour can be troublesome.

I have a v1 dishy (the round one), wired to its POE brick and then to the WAN2 port of my 2862. The 2862 gets two different WAN2 interface IPs off dishy and then SL via DHCP. So the WAN2 interface is running a DHCP client. it gets a 192.168.100.100 IP while dishy is looking for the SL network. Once dishy finds SL, whats supposed to happen is the WAN2 DHCP renew requests get passed through dishy (it stops answering) to a ground station dhcp server and the 2862 picks up a CG NAT IP for the WAN2 interface. The DHCP lease time is 5 seconds, so you shouldn't need wait very long for it to sort itself out... The 2862 instead seems to get stuck renewing the useless IP off dishy forever more. Lots of third party routers have this issue, hence some use the SL router between.... a recent firmware seemed to improve it a bit, but not entirely. hohum. anyway, the 2862 is running a dhcp server for my lan, so everything else gets its IP off the 2862. which is what you seem to be looking to do.

my guess would be your WAN2 interface is not configured right. its passing dhcp requests from your LAN out to the WAN port? So dishy is answering those too? did you enable bridge mode on the interface? might explain whats going on.