If different posters are using the same VPN, will the IP address be the same?

[TheHolleys87]

I’m slowly learning about VPNs and have a question that came up from an ongoing thread (I’m sure you’ll figure out which one). If several unconnected/unrelated people were using the same VPN, could the IP address their messages come from be the same? Or if the IP address is the same, then the posts definitely came from the same computer?

 

[bnoble]

It will appear to come from the VPN. However most commercial VPNs do not use just one address but rather a family of them.

 

[dioxide45]

I suppose it is possible, but what are the chances that two people who posted to the same thread just a couple days apart after signing up the same day just happen to also be using the same VPN service? Both also talking great things about a scam company? Answer is, slim to none.

 

[TheHolleys87]

I suppose it is possible, but what are the chances that two people who posted to the same thread just a couple days apart after signing up the same day just happen to also be using the same VPN service? Both also talking great things about a scam company? Answer is, slim to none.

That’s what I thought, but wondered about the technology!

 

[bnoble]

It is also fairly trivial to know whether someone is coming from a VPN, a corporate presence (which might also offer VPN services to employees), or something else.

For example, when I am VPN'd into campus, my IP address might be 35.7.41.39. But, if I do a "host lookup" on that IP address, I get:

% host 35.7.41.39
39.41.7.35.in-addr.arpa domain name pointer 0587671847.vpn.umich.net.

Pretty straightforward--I am coming in through the University of Michigan's VPN service.

In contrast, when my VPN is off, I end up coming from my home IP address. When I do a lookup on that, I get [address redacted]:

% host [redacted]
[redacted].in-addr.arpa domain name pointer [redacted].lightspeed.livnmi.sbcglobal.net.

Which is pretty clearly not a VPN, but rather a private fiber connection in southeast Michigan. So, if someone is claiming to be using a VPN, it's easy to at least get 90% sure that they are/are not telling you the truth. You can spoof the names if you manage to be a little nefarious with DNS, but that's getting pretty clever for an internet discussion board shill.

This is complicated by the fact that I happen to also run a VPN server in my house. It's a long story. But only family members use that server, unless one of them has been compromised and doesn't know it/didn't tell me.

 

[SmithOp]

I’m slowly learning about VPNs and have a question that came up from an ongoing thread (I’m sure you’ll figure out which one). If several unconnected/unrelated people were using the same VPN, could the IP address their messages come from be the same? Or if the IP address is the same, then the posts definitely came from the same computer?

I use a VPN to watch streaming content from other countries, it comes in handy to watch BBC and ITV from the UK. IP addresses can identify the general area you are from, VPN gets around location blocks.