PuTTY bug x11-proxy-crash

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summary: Proxy + SSH + X11 forwarding fails and/or crashes
class: bug: This is clearly an actual problem we want fixed.
priority: high: This should be fixed in the next release.
present-in: 0.53 0.53b 2002-09-29 2002-03-25 2002-12-11
fixed-in: 2002-12-19 8304f4e0dcd9555eb8dceb0402f1faa2738c2777 (0.54)

Opening a forwarded X11 connection over an SSH connection that's using a proxy fails to work. (Versions of PuTTY before 2002-10-11 may also crash.)

I (JTN) can reproduce this with HTTP proxying.

Appears to be occur regardless of whether there's an X server to connect to. When I do have an X server running, it doesn't appear to see any traffic when attempting X forwarding through a proxy.

Symptom is something like the following:

X connection to chiark:27.0 broken (explicit kill or server shutdown)

PuTTY behaves as though the X connection is being opened then slammed shut:

2002-10-17 18:07:24     Received X11 connect request
2002-10-17 18:07:24     opening X11 forward connection succeeded
2002-10-17 18:07:24     Opened X11 forward channel
2002-10-17 18:07:24     Forwarded X11 connection terminated

A workaround is to add `localhost,127.0.0.1' to the proxy exclusions. This implies that our proxying code is being over-enthusiastic and needs reining in.

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Audit trail for this bug.

(last revision of this bug record was at 2016-12-27 11:40:22 +0000)