DHCP question

[ImNotThere]

I'm at a crossroads with how to setup a theoretical network, 9 routers in total, 3 on each main "host" which all need DHCP setup on them, would it be more worthwhile to individually setup DHCP on each router or setup 3 DHCP servers for the routers?

[WereCatf]

11 minutes ago, ImNotThere said:

I'm at a crossroads with how to setup a theoretical network, 9 routers in total, 3 on each main "host" which all need DHCP setup on them, would it be more worthwhile to individually setup DHCP on each router or setup 3 DHCP servers for the routers?

You need to explain what you're trying accomplish better.

[mynameisjuan]

Always central management first, so DHCP server with DHCP relay on the routers. For ease of setup, configuring it on the routers themselves is not a bad option.

 

But this really depends on what the situation is here

[ImNotThere]

37 minutes ago, WereCatf said:

You need to explain what you're trying accomplish better.

The whole scope being 3 separate hosts trying to connect over a "large" distance, each with around 800 theoretical hosts

 

This will be a major route for communication, it's a bit hard to explain really

[mynameisjuan]

26 minutes ago, ImNotThere said:

The whole scope being 3 separate hosts trying to connect over a "large" distance, each with around 800 theoretical hosts

 

This will be a major route for communication, it's a bit hard to explain really

I'm confused at what you are referring to about the "3 separate host" and where DHCP is coming in play here.

 

This sounds more like a routing question

[ImNotThere]

Just now, mynameisjuan said:

I'm confused at what you are referring to about the "3 separate host" and where DHCP is coming in play here.

 

This sounds more like a routing question

I think I'm confusing myself here rip

 

Essentially it's a theoretical situation where 3 large cities have roughly 800 users each, I'd be using dhcp to ensure no duplicate ip addresses, the 3 routers would be configured so if one goes down there are 2 more still working.

 

If you wouldn't use dhcp there what would you use? Other than manually configuring all the users ips

[TerminalDuplex]

Sounds like you should just make DHCP servers and make sure that you configure your routers for forwarding broadcasted UDP packets to ensure the DHCP sequences make it across your network.

 

Need more info

[ImNotThere]

5 minutes ago, TerminalDuplex said:

Sounds like you should just make DHCP servers and make sure that you configure your routers for forwarding broadcasted UDP packets to ensure the DHCP sequences make it across your network.

 

Need more info

Okay, yeah sorry for the vague information, it's only an idea in my head, I havent really considered the topology of the network, just curious how dhcp should be used when theres so many hosts and routers

[WereCatf]

6 minutes ago, ImNotThere said:

the 3 routers would be configured so if one goes down there are 2 more still working

Sounds like you need virtual IP/IP-failover. You can't have three DHCP-servers serving the same network simultaneously.

[ImNotThere]

8 minutes ago, WereCatf said:

Sounds like you need virtual IP/IP-failover. You can't have three DHCP-servers serving the same network simultaneously.

just whipped this up quick, don't judge use of cables, this is more what i'm talking about, every pc would go into the DHCP server (via switches), then into the routers before being sent off, would something like this work?

 

@TerminalDuplex This is 1/3rd of the topology, if that helps any

[mynameisjuan]

13 minutes ago, ImNotThere said:

I think I'm confusing myself here rip

 

Essentially it's a theoretical situation where 3 large cities have roughly 800 users each, I'd be using dhcp to ensure no duplicate ip addresses, the 3 routers would be configured so if one goes down there are 2 more still working.

 

If you wouldn't use dhcp there what would you use? Other than manually configuring all the users ips

So essentially what I said in my first post. You want DHCP relay back to the server(s). You can configure multiple relays which is the dirty way where all 3 DHCP servers respond but the client only accepts 1. Or you can do IP failover on the servers themself with them all responding to the singlular ip or in an active/passive config.

 

8 minutes ago, WereCatf said:

Sounds like you need virtual IP/IP-failover. You can't have three DHCP-servers serving the same network simultaneously.

Yes you can. You can even them all responding to the same subnet. Part of the mechanism of DHCP from the server side is to send an ARP before handing out a lease. This is very hit or miss on vendors though with relay

[dalekphalm]

You just need to configure a big-ass DHCP server with failover - and ensure your switches are relaying it. Then you also need to configure router failover too if you want 3 routers in case one goes down - or you just do load balancing (or both failover w/ load balancing).