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So a previous tech left me a real mess that I am trying to figure out. The site receives internet from a cable modem with a dedicated IP. That modem goes to a sonicwall device with an IP address of 192.168.1.1 on a 255.255.255.252 subnet mask. It has DHCP disabled but the tech has set some static addresses on this network. No idea how many but I know they are mostly printers. The server is a Windows Server 2012. The server has an IP Address of 192.168.1.250 and a gateway of 192.168.1.1. The server is a DHCP server among other things and is providing a DHCP scope of 192.168.0.1 to 192.168.0.254 with a subnet mask of 255.255.255.252. It also hosts DNS. Here is my problem. The DHCP it is hosting is 97% full. I want to move the whole network to a class B but I can not do that until the summer when school is out. I came up with the idea of creating a superscope and creating a new class c with an address of 192.168.5.1 to 192.168.5.254 with a subnet mask of 255.255.255.0. I plan on moving devices that are internet only to that scope since I know that routing between scopes is an issue without helpers. I created the superscope and the 5.1 network and everything works with DHCP however I can not get to the internet. I am not sure exactly what I need to do here. The new scope has a dns of the server and a gateway of the router. I have compared settings with the working scope and all are the same yet I can not see the internet from scope 2. What am i missing here? Thanks.

4 Spice ups
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For the 5.x scope…are you using 192.168.1.1 as the gateway? You can’t. I need to think on this for a minute, but the subnet mask is screwy too on the 1.1 network. Umm, just a minute.

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Huh?

Umm…wrong subnet mask for that range - unless you are having a bunch of IP segments (multiple scopes) in that range.

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A few random thoughts:

  • How many hosts are you anticipating on each network? Do you need to run two subnets? Less complexity is best.

  • Are you using managed switches? VLANs?

  • Server 2012 or Server 2012 R2?

  • If you’re already changing the IP addressing, get off 192.168.x.x. Too many things use that as a default, and will cause trouble if you lose a configuration or someone does something stupid. Opt for 10.x.x.x.

  • Classed IP addressing is so 1980. Classless is where it’s at, daddy-o.

  • What kind of SonicWall device? Specifics are important.

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That subnet mask would make it so the sonicwall could only communicate with 192.168.1.1 - 192.168.1.64 or as this twisted up my brain so much I cant even think right? I know it is a /30 subnet which is 64 hosts.

owwww www .

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The gateway of the router should be the 192.168.5.0/24 IP address of the router right? If it is not in this IP scope, you will not get out (can’t get there from here).

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If the router is in the 5.x subnet yes. However, it shouldn’t be. It should be on the 1.x network in order to communicate with the Sonicwall (which I am assuming is a Firewall as it is connected to the modem directly) and then it can easily get out to the internet.

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The router should have a 5.x interface which has a static next hop of the 1.x interface for all internet traffic. there really isn’t quite enough info to make this work yet.

Also welcome to the community James. Orientation is next Thursday at 0400 Zulu

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Agree with others this is subnet masks gone crazy

You need to move to a /23 network to give yourself 512 IPs so 255.255.254.0

So document what every static device is and one Friday night take it all down and rebuild on the new range.

Assign the firewall 10.0.0.1 and then your static devices assign IPs and then create a DHCP scope for the rest of the network

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Umm…no. the gateway for the 192.168.5.0/24 network needs to be in the 192.168.5.0 network. The router can be whatever IP it wants to be as long as there is a route to it in the network. It may be another interface for the router or another device but the IP that the scope has to point to must be on the same IP network.

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Just realized my typo that caused the confusion - “The gateway of the router should be…” should have read “The gateway of the scope should be…”

I was typing fast and multi-tasking…sorry for any confusion.

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Ok so going to try to answer as many of the questions as I can. Like I said I did not make this mess I just walked into it and now have to figure it out. Router address is 192.168.1.1 that’s it. It has no other IPs I checked. The server has an ip address of 192.168.1.250 no additional I checked. The working scope has the following configuration. DHCP 192.168.0.1 to 192.168.0.254 with a subnet mask of 255.255.255.252. It has a DNS of 192.168.250 and a gateway of 192.168.1.1. It works as expected despite the mess and being nearly depleteded. But the new scope with the exact same settings just 1.5 instead of 0.1 does not. I get an ip address from the DHCP server but I can jot get anywhere. I will move to a 10.0.0.0 with a 255.255.0.0 over the summer but too many devices have to be reconfigured to move now. This craziness is making my head spin. I just want to survive it until the summer. The server is 2012 r2. No Vlans at all switches are dumb. No other servers on the network. Expecting about 400 devices total once expansion completes but that will not happen until after the summer. I just need to get by until then.

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The problem is the router shouldn’t be able to talk to anything outside of it’s IP network 192.168.1.1/30 = 192.168.1.1 - 192.168.1.2 (1.0 is the network address and 1.3 is the broadcast). There has to be a device (1.2) that is in the mix somewhere.

What about static routes? What are they on the router?

tracert from your .250 to the 1.1 router and see how many hops it takes.

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ah yes, now it makes sense. Yeah, no question, the GW must be within the scope.

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Thanks da Beast I am off site now but will do that in the morning

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Run a trace on one of the devices on the 0 scope too to see how it is hopping.