Gpg Agent is listening on port xyz

Werner Koch wk at
Fri Nov 18 09:54:28 CET 2011

On Fri, 18 Nov 2011 05:55, jw72253 at said:
> Hello. When my firewall advises me that GPG agent is "listening on:xyz",
> what exactly is it listening for and is that necessary?  Thanks.

On Windows we don't have Unix Domain Sockets.  The emulation we use
consists of a plain file giving a TCP port number.  The server
(e.g. gpg-gent) is listening on localhost and that port number.  The
client connects to localhost and that port number.  This emulation
yields semantics similar to a Unix Domain Socket.

We use this IPC mechanism for interprocess communication between gpg and
gpg-agent. gpg-agent and scdameon, etc.

Given that the server is only listening for connections from localhost,
this scheme is a pure local IPC mechanism. Unfortunately some firewalls
don't get it right and try to protect against attacks from one-self.



Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.

More information about the Gnupg-users mailing list