Correct Network IP addressing if your users have ability to VPN in

ipnetworkingvpn

My internal network is 192.168.0.x with a gateway of 192.168.0.1.

I have users that VPN into our firewall which then essentially adds them to the network.

However, if their home router has an IP address of 192.168.0.1 then of course we have all kinds of issues.

So, what is the ideal networking address setup to avoid this? I have seen setups where the remote users have router addresses in the 10.x range also so not sure what i can do to prevent this.

Any comments very welcome!

Best Answer

Techspot has A List of Common Default Router IP Addresses that helps with this. Usually home routers uses /24 subnets. Nowadays mobile phones are often used for sharing network connection, so we must take these ranges into account, too. According to the list we can deduce we should avoid:

  • 192.168.0.0/19 - most of the routers seems to use some of these, above 192.168.31.255.
  • 10.0.0.0/24 is also widely used, and Apple uses 10.0.1.0/24.
  • 192.168.100.0/24 is used by Motorola, ZTE, Huawei and Thomson.
  • Motorola uses (in addition) 192.168.62.0/24 and 192.168.102.0/24.
  • 192.168.123.0/24 is used by LevelOne, Repotec, Sitecom and U.S. Robotics (less common)
  • Some D-Links have 10.1.1.0/24 and 10.90.90.0/24.

We have three ranges reserved for private networks; we still have plenty of space to avoid these in:

  • 10.0.0.0/8
  • 172.16.0.0/12
  • 192.168.0.0/16

Some random upper range from 10.0.0.0/8 could be the safest choice for avoiding collisions. You may also want to avoid number 42 in any part of the IP address range: it might be the most common "random" number, as it's the Answer to the Ultimate Question of Life, The Universe, and Everything.

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