How to Configure NSX-T 3.0 as a DHCP Server

[@mrjazze1520]

@NRDY Tech, Hi Mike, although I'm experiencing an awful time with getting VMs to obtain DHCP addresses; I want to echo what everyone else has been commenting. You are doing an excellent job of explaining NSX-T. It's a shame VMware/Microsoft (I don't discriminate) webinars are so baked with marketing gibberish we barely get any meat and potatoes out of them. So I'd like to say, keep up with the great work!. I've spent the last two weeks deploying, reconfiguring, taring down and rebuilding my NXT lab seeking to get things working. Today, I finally got BGP peering between NSX-T and PFsense router working. However, every time I boot a VM connected to NSX segment, it brings down my edge tunnel ports preventing IP lease. Out of desperation I've now manually assigned address within segment and can ping it's gateway from VM and from my desktop. NSX Version 3.1.2.0.0.17884002, VCSA 7.0.2.00200, ESXI 7.0.2.17867351, pSwitch MTU=9000, VDS MTU=9000, NSX Global MTU=9000, using same VDS name for host/edge deployments, I'm using two different TEP VLANs for host and edge. Do you have any thoughts on what's is causing the tunnels to drop/down?

[@francoisgotti632]

HI Guy, How to proceed to add a specific generic DHCP option ? Option 11 and 17 are not available.

[@diegohidalgo8347]

Hey Mike your videos are the best, Can you cover the "Local Dhcp" for VLAN standalone backend segments Who are not conected to T0 or T1.

[@NRDYTech]

Hi Diego, as far as I'm aware, the ONLY way to use DHCP for a VLAN-segment, is doing it through the Service Interface (starting in 3.1.1). This basically means you could hand out DHCP IP addresses (from NSX-T) to non-VMs (on a VLAN segment). But if you have a VM on a VLAN-backed segment in NSX-T, I am not aware of a way to run DHCP for those VMs directly. Here's a link for reference: docs.vmware.com/en/VMware-NSX-T-Data-Center/3.1/administration/GUID-486C1281-C6CF-47EC-B2A2-0ECFCC4A68CE.html

[@diegohidalgo8347]

​@@NRDYTech Hi Mike thanks for the reply, I see... I was under the impression we still had the option to use local DHCP server from within the Policy UI in the Segment itself. So its meant for Physical VLAN consumers only

[@NRDYTech]

@@diegohidalgo8347 I'm not sure how that would work honestly - since the DHCP process runs on the edge nodes and not on the transport nodes. Not to say it isn't happening, but if so, is something new for me!

[@diegohidalgo8347]

@@NRDYTech you rock! Thanks bro

[@diegohidalgo8347]

​@@NRDYTech Hey Mike , it turns out Local DHCP does work for VLAN attached VMs. All config is from Policy/UI on the Segment itself its just not well documented but is possible. I figured you may be curious. Thanks

[@Slipknoted911]

Thank you brother

[@NRDYTech]

You’re welcome! Thanks for watching!

[@Jshaw0304]

I disagree with your tutorial a little bit. As far as I understand it, there is no requirement for the T1 to have a SR in order for you to have DHCP services running on the edge cluster. You need to specify a edge cluster in the DHCP profile, which instantiates the DHCP service on the edge nodes (1 Active / 1 Passive). I'm fairly confident that even if your T1 isn't associated with an edge cluster that you can still pull DHCP addresses. Also another point, you probably want to use Local DHCP server, not gateway so that you can specify IP blocks per segment.

[@harpreetmann9009]

Segments which will consume dhcp IP are connected to the Tier1 gateway . In order for T0 or T1 to provide stateful services they need Service Router component instantiated . In this case since its connected to T1 we have connected to edge cluster so that SR of T1 gets created on edge node . Local DHCP server will be within the L2 domain of that specific segment

[@Jshaw0304]

@@harpreetmann9009 I agree, but disagree because the use case is super niche. If you instantiate an SR for the T1 it changes the packet flow of everything connected. It seems like it would be better to just use the T0 to serve up DHCP unless there is an actual need for you to have a T1 SR in your environment. I could be missing the use case, but I can't really come up with any where I would want to instantiate a T1 SR and use DHCP services. I would likely be statically assigning everything off a T1 SR because of NAT,SNAT,LB, etc. tldr; Use SR on T0 instead of T1 unless you have another use case for a T1 SR

[@harpreetmann9009]

@@Jshaw0304 In that case if we want use Dhcp relay service or Gateway DCHP then better to have your segments directly connected to T0 . But that might not suit everyone

[@Jshaw0304]

@@harpreetmann9009 I disagree with that. DHCP functions nearly identical at the T0 SR as it does at the T1 SR, except you aren't modifying packet flow for your entire T1, only a small subset of traffic. If anything, putting DHCP at the T0 makes more sense for environments with multiple T1s off of a single edge cluster. Thousand ways to skin a cat and most people are probably using Infoblox or MS DHCP anyways.

[@harpreetmann9009]

@@Jshaw0304 Any centralised service which needs to be activated on Tier 0 or Tier 1 needs Service router for that specific Tier gateway . So In that sense router needs to be connected to edge cluster .