reading news over telnet

reading news over telnet

[Max Froumentin]

The domain my computer is connected to does not allow me to connect to
foreign HTTP servers (it firewalls out requests). I can always telnet
to some other machine outside that domain and start gnus there, but it
isn't practical at all. Is there a way to tell my local gnus to read a
foreign group by connecting to a particular machine first
(rlogin/telnet) and by fetching the group contents from there?

I suspect nntp-open-connection-function must be related to what I need
to do but I haven't figured out how to use it.

Max.

Re: reading news over telnet

[Max Froumentin]

I wrote:

> foreign HTTP servers

but I meant NNTP of course.

Max.

Re: reading news over telnet

[Kai Großjohann]

The node `Example Methods' in the Gnus info file contains two
examples, which seem clean enough...
kai
-- 
I like BOTH kinds of music.

Re: reading news over telnet

[Max Froumentin]

It is. Sorry I missed it. 
I still can't make it work though. Setting the foreign group's select method
as indicated:

(nntp "firewall"
   (nntp-address "cornucopia.maths.bath.ac.uk") ; my firewall machine
   (nntp-open-connection-function nntp-open-rlogin)
   (nntp-end-of-line "\n")
   (nntp-rlogin-parameters
      ("telnet" "news.freshmeat.net" "nntp")))

I restart gnus, and gnus apparently succeeds in talking to
news.freshmeat.net, since I get in my group buffer

       59: nntp+firewall:fm.announce

Right. But when I select the group, I get the "Fetching headers..."
message and it gets stuck.

I'll try and look deeper into that but now it's time to go to bed.

Max.

One more question, tough. Why isn't it possible that gnus connect
*directly* to the foreign server using telnet? Apparently talking to a
external news server through telnet works (through the firewall):

> telnet news.freshmeat.net 119
Trying 209.207.168.124...
Connected to freshmeat.net.
Escape character is '^]'.
201 freshmeat.net InterNetNews NNRP server INN 2.2 21-Jan-1999 ready (no posting).
LIST
215 Newsgroups in form "group high low flags".
fm.announce 0000000059 0000000001 m
.
GROUP fm.announce
211 58 1 59 fm.announce
HEAD
221 1 <7p9r4k$klt$1@core.freshmeat.net> head
Path: freshmeat.net!not-for-mail
From: freshd@freshmeat.net
Newsgroups: fm.announce
etc.

Re: reading news over telnet

[David S. Goldberg]

> One more question, tough. Why isn't it possible that gnus connect
> *directly* to the foreign server using telnet? Apparently talking to
> a external news server through telnet works (through the firewall):

Whatever your sysadmin told you, your firewall isn't blocking NNTP.
You aren't talking to that NNTP server with the telnet protocol in
this case, just the telnet program.  You should be able to have gnus
talk to the server directly too unless your firewall can detect a
connection from the emacs program versus one from the telnet program.
If that's the case just rename your emacs binary to telnet and you'll
be all set (do I really need the smiley here? :-)
-- 
Dave Goldberg
Post: The Mitre Corporation\MS B325\202 Burlington Rd.\Bedford, MA 01730
Phone: 781-271-3887
Email: dsg@mitre.org

Re: reading news over telnet

[Toby Speight]

David> David S. Goldberg <URL:mailto:dsg@mitre.org>

>> Why isn't it possible that gnus connect *directly* to the foreign
>> server using telnet?  Apparently talking to a external news server
>> through telnet works (through the firewall):


0> In article <m1bu2py9q9k.fsf@blackbird.mitre.org>, David wrote:

David> Whatever your sysadmin told you, your firewall isn't blocking
David> NNTP.

Unless the telnet program he's using has some non-standard magic
compiled into it (e.g. SOCKS support) that Emacs doesn't.

Not sure how to configure the Gnus nntp backend to use an external
telnet, though - is it in the manual?

Re: reading news over telnet

[David S. Goldberg]

David> Whatever your sysadmin told you, your firewall isn't blocking
David> NNTP.

TS> Unless the telnet program he's using has some non-standard magic
TS> compiled into it (e.g. SOCKS support) that Emacs doesn't.

Good point.  I haven't seen SOCKS used in so long I hadn't considered
it.  If that's what he needs, then he probably can have gnus telnet
directly to the host at port 119 though I don't know exactly what
variables he'd need to set.
-- 
Dave Goldberg
Post: The Mitre Corporation\MS B325\202 Burlington Rd.\Bedford, MA 01730
Phone: 781-271-3887
Email: dsg@mitre.org

Re: reading news over telnet

[Max Froumentin]

...is possible, even though I've had to modify the gnus source (commented
out 1 line):

AFAIK Whatever controls the traffic between the subnet here and the
outside world filters out NNTP as well as RLOGIN connections, but not
TELNET. This is why using 
(setq nntp-open-connection-function nntp-open-rlogin) doesn't seem to work.

nntp-open-telnet didn't work either but for a different reason: just
after reading the user password, nntp-open-telnet erases the terminal
buffer and then waits for a prompt:

	(process-send-string
	 proc (concat
	       (or nntp-telnet-passwd
		   (setq nntp-telnet-passwd
			 (mail-source-read-passwd "Password: ")))
	       "\n"))
	(erase-buffer)
	(nntp-wait-for-string nntp-telnet-shell-prompt)

What happens in my case is that the prompt is always written in the
buffer *before* the latter is erased. Thus nntp-wait-for-string
hangs. Everything seems to work when I comment out (erase-buffer).

My group parameters are now:

(nntp "firewall"
      (nntp-address "mary.bath.ac.uk")
      (nntp-open-connection-function nntp-open-telnet)
      (nntp-end-of-line "\n")
      (nntp-telnet-parameters
       ("exec" "telnet" "-8" "${NNTPSERVER:=news.freshmeat.net}" "nntp")))

I suppose I could send a patch or something to have this corrected in
the next gnus release, but with my limited knowledge of
gnus/emacs/elisp I'd rather be cautious and avoid damaging the nntp
backend...

Maybe someone who knows more than me will verify this change and
approve it.

Max.

Re: reading news over telnet

[Lars Magne Ingebrigtsen]

Max Froumentin <masmef@maths.bath.ac.uk> writes:

> nntp-open-telnet didn't work either but for a different reason: just
> after reading the user password, nntp-open-telnet erases the terminal
> buffer and then waits for a prompt:
> 
> 	(process-send-string
> 	 proc (concat
> 	       (or nntp-telnet-passwd
> 		   (setq nntp-telnet-passwd
> 			 (mail-source-read-passwd "Password: ")))
> 	       "\n"))
> 	(erase-buffer)
> 	(nntp-wait-for-string nntp-telnet-shell-prompt)

That looks like a bug.  I've now removed the `erase-buffer', but it
probably was these for some reason or other, so perhaps things will
break in other ways.  We'll see.

-- 
(domestic pets only, the antidote for overdose, milk.)
  larsi@gnus.org * Lars Magne Ingebrigtsen

Re: reading news over telnet

[Sam Falkner]

As Kai pointed out, the `Example Methods' node has examples of this.
However, I'd recommend looking at ssh if at all possible.  Try to get
ssh working through your firewall.  It might be impossible, but if you 
do manage to get it working, you can use ssh's proxy features to have
a cleaner solution.

- Sam