Privsep requires operating system support for file descriptor passing.
Compression will be disabled on systems without a working mmap MAP_ANON.
-PAM-enabled OpenSSH is known to function with privsep on Linux.
-It does not function on HP-UX with a trusted system
-configuration.
+PAM-enabled OpenSSH is known to function with privsep on AIX, FreeBSD,
+HP-UX (including Trusted Mode), Linux, NetBSD and Solaris.
-On Compaq Tru64 Unix, only the pre-authentication part of privsep is
-supported. Post-authentication privsep is disabled automatically (so
-you won't see the additional process mentioned below).
+On Cygwin, Tru64 Unix, OpenServer, and Unicos only the pre-authentication
+part of privsep is supported. Post-authentication privsep is disabled
+automatically (so you won't see the additional process mentioned below).
Note that for a normal interactive login with a shell, enabling privsep
will require 1 additional process per login session.