Does your site open from Russia?
A real diagnostic from our server in Russia. Not "is it on the RKN registry" — but whether the request makes it all the way through the network. We see DNS spoofing, IP blocks, SNI-based DPI and modern post-handshake drops (TSPU).
What exactly we check
Five sequential network layers — each responsible for its own class of blocking.
- 1
DNS resolution
We resolve the domain's IP via a system resolver in Russia. If the answer is 0.0.0.0, 127.0.0.1 or another obviously wrong address, the ISP is doing DNS spoofing.
- 2
TCP connection
We open a TCP socket to the resolved IP on port 443. A reset or timeout at this stage means the IP is blocked on the route — typical of address-list blocking.
- 3
TLS handshake
We send a ClientHello with the correct SNI. If the handshake breaks midway, the ISP sees the hostname in the clear and drops the connection. This is the classic SNI-based DPI block.
- 4
HTTP response + byte counting (the key part)
We make a real GET / with a browser User-Agent and stream the response body, counting every byte received. Modern TSPU lets the first ~32 KB through, then resets the stream. Without byte counting this is easy to miss — we see the break in the characteristic 8–64 KB window and flag it as a TSPU signature.
- 5
Page content
We check that the real site page came back, not an ISP stub page in its place.
How this differs from other checks
Only sees formal entries. A site can be blocked by DPI with no registry entry at all, or be on the registry yet still open at some ISPs.
We see what actually happens on the wire: whether DNS resolves, whether TCP opens, whether the response body makes it to the end.
HEAD gets no body — modern post-handshake blocking goes unnoticed, the status is a successful 200.
We download the body and count bytes. If the response cuts off at 32 KB, that's a modern TSPU signature — old tools don't see it.
If the site won't open, you can't tell at which level the problem is. DNS? Network? Certificate? Content?
Each layer is checked separately, and the report shows exactly where the failure happened and why.
If the site is down worldwide, not just in Russia, it's not blocking but a site problem. Without a comparison it's unclear.
In parallel we make the same request from servers outside Russia and compare. If it opens from abroad but not from Russia, the problem is in the Russian segment.
Want to monitor regularly?
This page is a one-off check. UptimeDog can watch your site continuously: checks every 30 seconds, Telegram and Email alerts, and a dedicated monitor from a Russian vantage point.