this post was submitted on 04 Oct 2023
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Privacy
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I don't get it... How does this protect anything? If we want our packets to reach a web server, we need to write the server's IP address on them. If a snooper has the IP, can't they just lookup the domain name from a DNS server? Or is that not a service DNS provides?
If the IP address is encrypted, how will the routers know where to send the packets? Only solution I can think of would be onion routing... Am I wrong??
An IP address is no longer associated with just one website/domain name. There could be thousands of websites running on a single IP address.
As is, anyone can currently look at your encrypted traffic and see in plain text which site you're surfing to. So this proposal is long overdue.
A government will still subpoena the destination IP for the information if they want it.
ECH protects against warrantless monitoring and other non-government bad actors and I'm happy to see it implemented. If there hasn't been a strong enough privacy argument to use Firefox for someone to date, this is a big one.
somebody wiresharking your traffic can see the domain name you're contacting even if you use https; this solves that.
reverse DNS lookup does exist, but it's not always accurate, especially when multiple websites are hosted on the same server (which is more common than you think)
Is it because of the "Host" HTTP header? I always thought it was optional, since the IP address and port were handled by the network and transport layers respectively. Turns out it's required to resolve between different virtual hosts in the same server. Today I Remembered (TIR?) that virtual hosts are a thing...
Is there anything else that might indicate the domain name in the handshake connection?
The SNI (Server Name Indication) happens before any HTTP communication and is done in plain text. It is needed because a single web server might host multiple websites, since each of them has their own certificate it needs to know which one to serve you.
With the new proposal that SNI is now encrypted. It makes the difference between anyone listening in being able to tell "you visited lemmy.world" and "you visited something behind Cloudflare".
Technically DNS will let you look up a host name from an IP address, but the catch is that it might not work: it's not automatically configured. And even if it is configured you might not get all of the host names pointing at that address.
Very many webserver operators don't bother adding the server's host name to reverse DNS. For example,
lemmy.world's IP address does not map to any host name in reverse DNS, andgoogle.com's IP address maps to some completely different name for me, with no mention of Google in the returned name.Also, many websites can be served from the same IP address, especially if they are hosted in the cloud. You are correct that someone snooping on the connection would still see the IP address, but if that points them at something like a webhosting company or a CDN (or some other server hosting many different sites) it still doesn't really tell them which specific site is being accessed.
But yes, if the site you're accessing is the only one hosted on that server then the snoop could potentially guess the host name. But even then: how would they know that's the only site hosted there? If some site they've never even heard of uses the same IP address they would never know.
You need to read how SNI works, then it will make sense