[Pan-users] Re: 1. Re: Can post, but cannot reply (Duncan)

[Duncan]

Karl Lindholm <address@hidden>
posted address@hidden, excerpted below, on 
Tue, 28 Oct 2008 06:35:59 -0700:

> Today's Topics:
> 
>    1. Re: Can post, but cannot reply (Duncan)

Interesting.  I had not seen the digest format for the pan groups, tho 
I've of course seen it for others I don't follow quite so closely...  
It's good it has the edit subject reminder.  That's the first time I 
believe I've seen that.

> Date: Sun, 26 Oct 2008 20:56:52 +0000 (UTC)
> From: Duncan

>> Karl Lindholm posted as excerpted below,
>> on Sun, 26 Oct 2008 06:16:08 -0700:
>>> 
>>>I have Pan setup to receive the Airline Pilots
>>> Assn. newsfeed. I can read and post, bit cannot reply to an existing
>>> message on the board. When I try to do so, the little "posting" window
>>> pops up and just grinds away, never actually sending the message.
> 
>> There's a reason pan doesn't do HTML.  Please respect that
> 
> Yahoo is the only mail client I use that does not have a "Users prefer
> to receive" field, I forgot that, and forgot to turn off the "Rich
> Text".  Sorry about that.

Thanks. =:^)

BTW, if you're interested in getting other lists (including the pan 
lists, if desired) served as news, checkout gmane.org.  Lars has both a 
web and a news interface running there, and there are hundreds of lists 
available, mostly computer oriented but there's also culture, science, 
recreation, politics, and org type lists.  I don't see ALPA or airline 
(it'd probably be under org), but if the list admin doesn't object, Lars/
gmane do add lists regularly, and can even backfill posts from before the 
list was added to gmane, if there's an appropriate archive available.

Just thought you might be interested if you're already trying to get ALPA 
working like that.

>> The problem sounds like something server-side.  Note that you can run
>> pan from a terminal window and get some additional output.  There's
>> also an undocumented --debug switch you can feed it, to get even more.
>> Try that and see if it spits out anything useful.
> 
> Will give both a try.  There is at least one more Linux/Pan user on the
> boards, and he initially had troubles, but it's been long enough he
> cannot remember how he solved it.  There are indeed a number of server
> problems, but this is the one that makes the least sense - given I *can*
> post

Indeed.  That's just weird.

>> Of course you can also try logging the network activity (most firewalls
>> have a log mode) if desired, to see what's actually happening on the
>> wire, or strace or gdb pan, altho it's not likely the latter two would
>> be a lot of help in this case.
> 
> Since I don't know what the latter two are, guess I will go with the
> first.

strace is (I think) short for system-call trace.  It runs on Linux (and 
possibly other *ix, I don't know) and when run, sits between the kernel 
and the program it's tracing, logging any calls to system/kernel 
services, so file activity, etc.  It's great for finding just what files 
a program is looking for, say if you can't figure out where it's storing 
its config.  The output can be overwhelming, however, unless filtered 
down to something interesting.  (You'd be amazed at how many fonts and 
icons and libraries and config files a program often looks for, many 
times in several places before finding the one in use on a particular 
system.  Try it sometime, it'll give you a new appreciation for all the 
work a computer does when a program is opened!)  I really don't know how 
much network info it might log, beyond the socket ops themselves, of 
course.

gdb is the GNU debugger.  It works best if programs are compiled with the 
function and etc symbol information, for debugging purposes, but can be 
useful even if not, for backtracing in the case of crashes, etc.  You 
could use it to see exactly what pan's doing as it does it, but it works 
best in the hands of a programmer that knows how C/C++/etc work.  Having 
the code of the program in question available is of course a bonus.  At 
this point it's probably too low a level for the type of stuff we're 
after, as strace likely is as well, which is why I implied they are good 
tools, but said they'd not likely be of much help in this case.

>> But it is certainly weird that you can post but not reply.  I'm
>> assuming there are other replies, so you know the server actually takes
>> replies...
> 
> Yes, though most of the posters either use the web interface, or the
> e-mail interface.  The gentleman I mentioned using Pan can and does post
> replies and is one of the moderators.  I do know he has complained that
> any post done from a newsreader has to be approved individually by him
> or another moderator, while the replies via the web, or e-mail do not. 
> ALPA is aware of this, but seems disinterested in fixing it.

So the group is effectively moderated?  That's a rather different 
dynamic, and indeed, it's not unusual at all for the config for moderated 
groups to be rather messed up on a news server.  Now knowing it's 
moderated, I'd almost lay money on it being a server side issue.  I'm 
guessing what that other individual did to fix the problem was become a 
moderator, therefore bypassing rather than really fixing the problem.

The deal is that for moderated newsgroups, the server accepts the posts, 
then forwards it (normally by mail) to the configured moderator address 
for approval.  If they approve it, they then post it, along with an 
appropriate approved header.  I'm not sure of all the details of how the 
approval process works, but do know that unless additional steps (pgp/gpg 
signing, etc) are taken, it's relatively easy to forge moderator 
approval.  In fact, there was (is?) one famous hacking group that was 
"self-moderated".  That is, it was marked moderated on the server, but 
with a deliberately invalid approval address.  Anybody could post -- 
provided they had the necessary skills to forge the approval header!  
Thus the moderated bit self-selected for hackers with at least /some/ 
skills, keeping the noise level down.

Obviously there's several points at which a server config can be wrong 
with such a setup.  Individual group moderator addresses can be wrong, or 
the mailer functionality can be entirely broken on the server, among 
other things.  Since moderated groups aren't the norm (for normal news 
servers, anyway), even if it's the mailer functionality broken and thus 
all such groups, it can go for days, weeks, months, before someone who 
knows enough about how moderated groups work contacts the server admin 
and asks whats going on.  Of course, if it's a single group's moderator 
address, that's compounded and it could be wrong for years before someone 
in the know notices and notifies the admins.

In this case, presumably there's only a few groups/lists, or maybe just 
the one.  But if few enough use the news interface, it could still be 
broken, particularly since it has the additional complication of being 
moderated, and from what you say, apparently is broken.

> Pan does not display threads like I would expect or prefer, but that'll
> be the subject of another post.  I'll try to get the error messages in
> more detail as described above first.

In general or just for this group?  If it's in general, yeah, another 
problem.  If it's just for this group, then it could be related, 
particularly since the references header is what's used for threading, 
AND is the only real difference between original posts and followups.

>> Similarly you can check the headers (IIRC by default, the "h" key
>> toggles full header display) of existing messages and verify that they
>> have a references header.  Again, if they don't, that could well be the
>> problem, probably due to the way the server is configured, as I said.
> 
>> This assumes a reasonably modern pan, 0.133 being the latest, not the
>> old 0.14.x series, pre-rewrite.
> 
> I run Ubuntu 8.04 - the repositories have 0.132 as the available
> version, so it is likely new enough to not be what you describe above.

Yes, it's new enough.

FYI however, the original 0.132 (and earlier) had a buffer overflow issue 
with *.nzb files, including pan's own tasks.nzb task list file.  Normally 
this just lead to a crash if the file was somehow corrupted, but it could 
be a security issue if someone specifically targeted it.  There's a patch 
available that was included in 0.133 along with various other fixes (it 
was a bugfix only update, pretty much).  Ubuntu /may/ have applied that 
fix and security-updated its 0.132, or may not have, I don't know.  It's 
probably worth checking, however, because there /are/ security 
implications.  Just take a look in the package changelog and verify that 
it mentions a security patch, maybe mentioning for nzbs or a buffer 
overflow, but AFAIK there's been only one such patch in anything like 
recent history, so if it mentions any security patches in say the last 
year, you're fine.  If you need to upgrade and have trouble, either ask 
here or contact one of the guys listed on the pan download page for 
Ubuntu packages.

(If you can confirm they DID update it, it'd be appreciated, so I don't 
have to keep mentioning it every time someone mentions 0.132 from 
Ubuntu.  FWIW I run Gentoo, and I don't believe anyone's said whether 
Ubuntu caught that security upgrade or not, so I haven't the foggiest.  
Hopefully 8.10 has 0.133 and I'll not have to worry about it.)

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman