How to use non-standard imap port?

[Nikolaus Rath]

Hello,

I'd like to connect to a non-standard IMAP port (8421). I've added a
(nnimap-server-port "8421") entry to my nnimap entry in
gnus-secondary-select methods.

However, when I attempt to start Gnus the connection to the imap server
fails with

| Warning: Unable to open server nnimap due to: Wrong type argument: stringp, nil

I've tried to set nnimap-server-port to 8214 (instead of "8421")
instead, but that did not work either.

I've enabled "Enter Debugger on Error", but for some reason the debugger
is not actually entered (I assume Gnus somehow catches the error?).

I've also single stepped through the nnimap-open-connection-1 function,
but it runs just fine, so the error is happening at some later point.


Does anyone have a suggestion what I can do to find out where the
problem is?


Best,
-Nikolaus

[Nikolaus Rath]

Hello,

It turns out I mis-diagnosed the problem. It's not setting
nnimap-server-port to "8421" that's causing the problem, but the setting
of nnimap-stream to plain. Using tls or network works just fine, but
encrypts the connection (and I want to look at it in Wireshark).

Anyone have a suggestion how to find out where exactly this setting is
causing problems?

Thanks,
-Nikolaus

Post by Nikolaus Rath
Hello,
I'd like to connect to a non-standard IMAP port (8421). I've added a
(nnimap-server-port "8421") entry to my nnimap entry in
gnus-secondary-select methods.
However, when I attempt to start Gnus the connection to the imap server
fails with
| Warning: Unable to open server nnimap due to: Wrong type argument: stringp, nil
I've tried to set nnimap-server-port to 8214 (instead of "8421")
instead, but that did not work either.
I've enabled "Enter Debugger on Error", but for some reason the debugger
is not actually entered (I assume Gnus somehow catches the error?).
I've also single stepped through the nnimap-open-connection-1 function,
but it runs just fine, so the error is happening at some later point.
Does anyone have a suggestion what I can do to find out where the
problem is?
Best,
-Nikolaus
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[Nikolaus Rath]

Post by Nikolaus Rath
Hello,
It turns out I mis-diagnosed the problem. It's not setting
nnimap-server-port to "8421" that's causing the problem, but the setting
of nnimap-stream to plain. Using tls or network works just fine, but
encrypts the connection (and I want to look at it in Wireshark).
Anyone have a suggestion how to find out where exactly this setting is
causing problems?

Reported (with patch to fix it) at https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20653.


Best,
-Nikolaus

[Nikolaus Rath]

Post by Nikolaus Rath
I've enabled "Enter Debugger on Error", but for some reason the debugger
is not actually entered (I assume Gnus somehow catches the error?).

To answer that part of the question myself: the reason is that Gnus uses
condition-case to catch the error (presumably so it can still attempt to
open any other servers).

To enter the debugger, one has to either use debug-on-signal (but that
gives a lot of other debugger invocations as well), or change the
problematic condition-case to condition-case-unless-debug.

Best,
-Nikolaus