[Discuss] SSH options (was Future of X11 (was Trying to connect to internet in Debian))

[richard.pieri at gmail.com (Rich Pieri)]

On Sun, 18 Jan 2026 19:31:07 -0800
Kent Borg <kentborg at borg.org> wrote:

> I thought -X was X11 forwarding.

Yes: -X forwards X11 traffic.

> And -A is ssh agent forwarding.

Yes: -A forwards SSH agent traffic.

> But then what is -Y? How is it different from -X? The name sounds all 
> secure, so does that make it related forwarding ssh credentials?

The X11 SECURITY extension allows you to mark X11 clients as trusted or
untrusted. Development was abandoned in the 1990s because hardly anyone
used it, but the code still lives in X.Org. Problem is, clients marked
untrusted don't work as expected and often not at all. -Y says "forward
X11 SECURITY trust". In practice it marks your X11 clients as trusted
which bypasses the extension so that they work correctly.

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