The MITM case reached its origin by address, so it depended on the
certificate 3proxy spoofs carrying an IP alternative name. It does when the
upstream certificate is copied, which is what happens on Linux and macOS
but not on Windows, where the client then refused the connection. Point a
name at 127.0.0.1 with nsrecord instead, and check the chain rather than
the name: an intercepted certificate names the upstream host, not the one
that was asked for. The log assertions gain from it too, since the name is
better evidence than a port that the request was seen.
nsrecord needs nserver as well as nscache, and has to follow nscache, so
say that in the manual: the record goes into the table nscache allocates,
and the table is only consulted when nserver is set.
The port-range fallback was exercised with a range the same case had
already used, so on a busy machine it could fail to bind for the ordinary
reason rather than the one under test. Use privileged ports, which nothing
can take.
When a case fails, print what its servers wrote: the reason usually goes to
the server's stderr, which was captured and then thrown away.
Three arrangements, with key material generated for the run rather than
kept in the tree: a proxy wrapped in TLS, a proxy that reaches a TLS parent
and verifies it against the CA, and MITM.
The MITM case checks what interception is for: the decrypted request line,
URI and all, reaches the log, where the same request through a plain
CONNECT tunnel leaves only the host and port.
The origin runs in its own process there so the proxy log holds only what
the proxy saw, and log assertions wait, since a record is written when the
connection finishes rather than when the reply arrives.
Verification of the spoofed certificate is deliberately not strict: 3proxy
issues those without an Authority Key Identifier, which Python rejects
under its 3.13 defaults.
