Given a LAN with default gateway of and subnet of

The DHCP range is currently set in the range of to

The 10.5.1.x range is reserved for static IP's.

I want to increase the DHCP pool ( the 10.5.2.x - 10.5.3.x range is too small )

Is this DHCP scope limited to the 2.x and 3.x range because of the subnet?

I cannot change the subnet in this scenario. When I try to add another range to the DHCP server ( i.e 10.5.4.x ) it will not allow it ( illegal range? )....

It's a Sonic Wall .. Model: PRO 300 (CPU: StrongARM / 233 Mhz) Firmware version:

  • Any reason you're using the sonicwall for your DHCP server? As you mentioned that is a pretty old Sonicwall. I don't even see it listed on the www.mysonicwall.com web site for any updates. Since you mentioned this is an 'Inherited' network, if you have other servers, you might look to migrate them away from that. Build the customers confidence up by saying that's a poor place to put your DHCP server for such a LARGE dhcp range. – Nixphoe Aug 18 '11 at 17:33
  • I did replace it with an available OS X server which I could control a wider range of addresses. But having that OS X Server do DHCP for some unknown reason prevented 10.5 clients from accessing a 10.5 server via AFP. Never figured that out so went back to the Sonic Wall.. – mozzer Aug 18 '11 at 18:02

As posted in the comments, SonicWall does routinely limit the number of devices their products will manage. Sometimes they offer "licensing upgrades" as options and sometimes it is a hard limit based upon the particular model.


The Netmask only defines the first two octets to be your networks fixed address part. So every 10.5.. combination should be fine from the netmask standpoint.


Without knowing what DHCP server you're using and exactly how you've configured it, I can't speak to the errors you're getting or what could be causing them, but I can say that there is nothing inherent in the protocol or what you're trying to do that should be a showstopper -- you should be able to assign anything within as a DHCP range (assuming nothing not in evidence that would preclude that from happening). I could speculate at length as to what your DHCP server is doing wrong, but it wouldn't be productive.

  • It's a Sonic Wall .. Model: PRO 300 (CPU: StrongARM / 233 Mhz) Firmware version: Pretty outdated , maybe that is my hangup. Looking into that – mozzer Aug 18 '11 at 12:44
  • Please add diagnostically-relevant information to your question, as an edit. – womble Aug 18 '11 at 12:47
  • It might be licensing limits on the device itself. – user48838 Aug 18 '11 at 12:49
  • @user48838 I looked in the embedded docs and found this :"Tip! The SonicWALL DHCP server can assign a total of 254 dynamic and static IP addresses. Post comment as answer and I'll accept – mozzer Aug 18 '11 at 17:57
  • @mozzer it looks like you should have enough "ammo" to get the network in order then, if that is your goal. – tkrabec Aug 18 '11 at 18:04

Why do you have such a large network range, on what appears to be a single subnet?

The more hosts you have on a network the slower it goes even with switches (there is a magic number, but it depends on the type of traffic & amount of traffic).

I would look at segmenting the network into smaller groups such as 10.5.x.0/24 (thus making several private class C's out of your class A). Then put a DHCP server on each subnet, this can be done with a single linux server that can also route the traffic (with-in your org) & hand it off to the sonicwall for internet routing.

  • 'Inherited' network ... – mozzer Aug 18 '11 at 17:24
  • 1
    Ouch, I'de use this as an opportunity to get the problem fixed rather than band-aid it. It could be a pretty easy sell, if you've got slow applications & data transfers. Not to mention it could help prevent the spread of malware/worms since they don't often scan for hosts off their subnet. – tkrabec Aug 18 '11 at 17:42
  • Classful addressing died nearly 20 years ago, and even then a /16 was a class B, not a class A. – womble Aug 18 '11 at 21:16

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