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RV220W can't create subnet

I'm trying to setup this router with my IP range to but if I try to enter a subnet mask other than I get the error - Invalid subnet mask. It should be 255 for given class of IP address at

Every other device on my network allows that subnet mask, why not this router, it's stopping access from my 192.168.101.x devices.


The small business products are designed to support class C networks. The small business switches do allow class B networking as they're also designed to integrate in to Enterprise networks. However, the routers are not.

Please rate helpful posts

-Tom Please mark answered for helpful posts

Thanks for the update, but, wow! that's poor, back to Draytek or Netgear then I guess.


Geeez... I've never seen such reasoning to create an artificial  limit. Has it ever occurred to anyone at cisco that sometimes people  want to use different blocks within an IP-range for different types of  clients while in the same subnet. You've got to be kidding...

One more reason to never buy cisco again...

The support is IMHO already below average, firmware updates are  extremely sparse for a new product and create new errors which are so  obvious that I'm sure there's hardly any quality control...

I've had a Draytek router before this one. The only reason I  needed a new router was because of the speed of my fiber internet  connection which the (old) Draytek couldn't handle.

If I had known al these things I would never have bought the RV220W...


Got the same problem with an RV180. However it will support class B  addresses, but you have to use the address range to, you can't use a subnet mask other than  for class C addresses in the range to

In other words they enforce network masks that give local address ranges as specified in RFC791

This is a bit ironic becauses Cisco's own document "IP Addressing and Subnetting for New Users" (

Document ID: 13788 )


Note:  Also note that the terms "Class A, Class B" and so on are used in this  document to help facilitate the understanding of IP addressing and  subnetting. These terms are rarely used in the industry anymore because  of the introduction of classless interdomain routing (CIDR).

This  is a pain because our private address range begins 192. , and  originally had a subnet mask of, but when we outgrew that  we increased it to


Besides the problem of no cisco vendor wanting to sell me the extended support for the rv220w I just wish I had seen this thread before I purchased. I have 3 class C I need to support on the 192.168.x.0 and it is driving me crazy on how to make it work. A simple class /23 of this network would sort of work .. but being foced to use /24 seems a little unusual. Ahh well .. I have a new netgear on the way and this will end up in my electronics garbage heap unless Cisco can put out a better firmware for it.


my rv220w has been collecting dust for the past two years .. the updates are slow to come out with reported vulnerabilities and they are still hamstringing us for not being able to afford enterprise firewalls for little things.. like being able to configure classless networks. I have since moved on to a small low power PC with pfsense and could not be happier.

As a note .. the rv220w runs on linux so you can request the latest source code tree and recompile it to be able to run classless networks. I am just not convinced it is a secure platform. I still run Cisco small business routers in my business (and love them) .. but the small business firewalls I will be avoiding.


Thanks for sharing :)  Honestly, I never used the firewall nor VPN function of that RV220W, we just treat it as a NAT router for internet access in the office :)


Hi Everyone facing the same problem,  

Just found out that, the Class C subnet limitation is only done on "client side javascript", with a little of trick using Chrome's Inspect function, you can modify the runtime copy of the javascript locally and bypass the checking.  I've successfully set the subnet on LAN IP setting!

Firmware version

Good Luck!


This is now possible in the FW You can add the MASK you wish!