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In our case, we were setting up VPN tunnels to a partner, who for some reason required that the addresses on our side should (appear to be) public IP addresses.

by twic 6y ago

In our case, we were setting up VPN tunnels to a partner, who for some reason required that the addresses on our side should (appear to be) public IP addresses. So we couldn't use 10/8 or 192.168/16 in (that part of) our network. They didn't actually need the addresses to be routable from the public internet (that was the whole point of the VPN). I think the requirement was really a way of making sure they were unique. I'm sure they had several partners who used 10/8 internally.

GekkePrutser 6y ago
There's also 172.16/12 :) But yeah I agree. If you're running a VPN for a large company it's kinda hard to avoid such conflicts. In my work we use 10.0.0.0/8 but of course some people use the same at home even though 192.168/16 is way more common. In general I find 172.16/12 the least common in the field.
- jamiek88 6y ago
  I know the old Apple extreme and time machine routers used to default to 10 rather than 192 ever since then I’ve kept my internal routing within that block. It just looks nicer to me which shows the power of Apple and how easily I am influenced.
- simondotau 6y ago
  I personally use a range towards the end of the 172.16/12 reservation for my home network for exactly this reason. Ever since I made the change five years ago I’ve never suffered any conflicts when running a VPN in or out.
  - bombcar 6y ago
    Virtually nobody realizes 172.17-172.31 are available. And many are surprised to find that there are 172.* that are routable.
- bombcar 6y ago
  A trick is to use something in the 10 range but not /8 - 10.185.203/24 will work on a 10/8 network (assuming no actual host overlap) as it’s more specific and will route first. Still gives you fun issues though.
- mrweasel 6y ago
  I like the 172.12/16 to company network, especially small companies with limited support resources. Getting employees on VPN is much simpler as virtually no home routers use that range.

by twic 6y ago

GekkePrutser 6y ago

There's also 172.16/12 :) But yeah I agree. If you're running a VPN for a large company it's kinda hard to avoid such conflicts. In my work we use 10.0.0.0/8 but of course some people use the same at home even though 192.168/16 is way more common. In general I find 172.16/12 the least common in the field.

jamiek88 6y ago
I know the old Apple extreme and time machine routers used to default to 10 rather than 192 ever since then I’ve kept my internal routing within that block. It just looks nicer to me which shows the power of Apple and how easily I am influenced.
simondotau 6y ago
I personally use a range towards the end of the 172.16/12 reservation for my home network for exactly this reason. Ever since I made the change five years ago I’ve never suffered any conflicts when running a VPN in or out.
- bombcar 6y ago
  Virtually nobody realizes 172.17-172.31 are available. And many are surprised to find that there are 172.* that are routable.
bombcar 6y ago
A trick is to use something in the 10 range but not /8 - 10.185.203/24 will work on a 10/8 network (assuming no actual host overlap) as it’s more specific and will route first. Still gives you fun issues though.
mrweasel 6y ago
I like the 172.12/16 to company network, especially small companies with limited support resources. Getting employees on VPN is much simpler as virtually no home routers use that range.