I deployed Chatmail Relay on my VPS with a clean IP and a clean domain. After deployment, the homepage was blocked by DPI! It can only be accessed from Russia via VPN! How is this possible?
Grok says the following:
DPI can react to certificates (for example, Let’s Encrypt), HTTP headers, or even QR codes for account creation if they resemble templates from banned services.
Port 25 is also blocked and only works via VPN.
Which hosting provider do you use? It could be that the hosting provider itself is blocked.
h o s t k e y. r u. No, they don’t block it. When I deployed it, I contacted tech support to ask them to open the necessary ports, and they did.
The website is really just a static webpage hosted on nginx, so unless there is active probing going on it’s not distinguishable from you hosting a static website. With TLS 1.3 (any modern browser uses this) certificate itself is not visible as well, only the SNI.
Delta Chat connecting to the server may be distinguishable, also if you ran the tests, but if the website was blocked right after deployment there is likely something else going on, e.g. the IP address maybe is already blocked or there is some boring routing problem with the allocated IP address.
Probably renting a server on Yandex.
I don’t know what you did there, but the Russian deltachat.ru server is working fine.