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0 pointslewiscollard1y ago0 comments

Depending on the web server's configuration, you very much _can_ find the domain which is configured on an IP address, by attempting to connect to that IP address via HTTPS and seeing what certificate gets served. Here's an example:

https://138.68.161.203/

> Web sites prove their identity via certificates. Firefox does not trust this site because it uses a certificate that is not valid for 138.68.161.203. The certificate is only valid for the following names: exhaust.lewiscollard.com, www.exhaust.lewiscollard.com

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jchw1y ago

I don't think that does you any good for Cloudflare, though. They will definitely be using SNI.

kelnos1y ago

That doesn't really matter, though. While OP is using Cloudflare, the actual server behind it is still a publicly-accessible IP address that an IPv4 space scanner can easily stumble upon.

jchw1y ago

I misunderstood, I thought the subdomain was an R2 bucket. If it's just normal Cloudflare proxying to some backend this is probably the most likely answer.

That said, while I think it's not the case here, using Cloudflare doesn't mean the underlying host is accessible, as even on the free tier you can use Cloudflare Tunnels, which I often do.

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0 pointslewiscollard1y ago0 comments

https://138.68.161.203/

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jchw1y ago

I don't think that does you any good for Cloudflare, though. They will definitely be using SNI.

kelnos1y ago

That doesn't really matter, though. While OP is using Cloudflare, the actual server behind it is still a publicly-accessible IP address that an IPv4 space scanner can easily stumble upon.

jchw1y ago

I misunderstood, I thought the subdomain was an R2 bucket. If it's just normal Cloudflare proxying to some backend this is probably the most likely answer.

That said, while I think it's not the case here, using Cloudflare doesn't mean the underlying host is accessible, as even on the free tier you can use Cloudflare Tunnels, which I often do.

1 more reply

j / k navigate · click thread line to collapse