What to test here
This page issues parallel requests to all hostnames and shows which protocol was actually negotiated for each connection. It is useful for a quick overview of what your browser and any intermediate SSE gateway are using across the full hostname matrix in one view.
Note that all hostnames resolve to the same IP and share a wildcard TLS certificate. Browsers coalesce parallel requests onto an existing connection when the IP and certificate match — so most rows will show the protocol negotiated for the initial page load, not what an isolated fresh connection to that hostname would use. Per-hostname protocol enforcement is only visible at connection establishment time (TLS ALPN, DNS HTTPS records). To test that reliably, navigate to each hostname directly via the Hosts page.
HTTPS — port 443
| Hostname | Expected | Detected |
|---|---|---|
sse-testcenter.org |
H3 H2 H1 | |
www.sse-testcenter.org |
H3 H2 H1 | |
h1-h3.sse-testcenter.org |
H3 H2 H1 | |
h2-h3.sse-testcenter.org |
H3 H2 | |
h1-h2.sse-testcenter.org |
H2 H1 | |
h2.sse-testcenter.org |
H2 | |
h1.sse-testcenter.org |
H1 | |
h3.sse-testcenter.org |
H3 |
HTTPS — port 8443
These hostnames advertise port 8443 via DNS HTTPS records (RFC 9460). Detection uses the explicit port so results are reliable regardless of DNS cache state.
| Hostname | Expected | Detected |
|---|---|---|
h2-8443.sse-testcenter.org |
H2 | |
h3-8443.sse-testcenter.org |
H3 | |
h2-h3-8443.sse-testcenter.org |
H3 H2 |
Cleartext hostnames
Cleartext hosts (h1c, h2c, h1c-h2c, and the
port 8080 variants) cannot be probed from this HTTPS page — browsers block
mixed HTTP/HTTPS requests. Use curl instead:
curl -s http://h1c.sse-testcenter.org/api/protocol curl -s --http2-prior-knowledge http://h2c.sse-testcenter.org/api/protocol curl -s --http2-prior-knowledge http://h2c-8080.sse-testcenter.org:8080/api/protocol