Date: Mon, 10 Feb 2003 10:32:12 +0000 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: FreeBSD-questions@FreeBSD.ORG Subject: Re: How to change Telnet Prelogin message? Message-ID: <20030210103212.GB49154@happy-idiot-talk.infracaninophi> In-Reply-To: <20030206225954.GC538@sub21-156.member.dsl-only.net> References: <1461.192.168.1.10.1044505050.squirrel@email.unixhideout.com> <20030206044512.GR87743@sub21-156.member.dsl-only.net> <20030206092721.GB53194@happy-idiot-talk.infracaninophi> <20030206192321.GA538@sub21-156.member.dsl-only.net> <20030206194716.GC58257@happy-idiot-talk.infracaninophi> <20030206215512.GB538@sub21-156.member.dsl-only.net> <20030206223453.GD58257@happy-idiot-talk.infracaninophi> <20030206225954.GC538@sub21-156.member.dsl-only.net>
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On Thu, Feb 06, 2003 at 02:59:54PM -0800, Nathan Kinkade wrote:
> On Thu, Feb 06, 2003 at 10:34:53PM +0000, Matthew Seaman wrote:
> > On Thu, Feb 06, 2003 at 01:55:12PM -0800, Nathan Kinkade wrote:
> > > On Thu, Feb 06, 2003 at 07:47:16PM +0000, Matthew Seaman wrote:
> >
> > > > Interesting. The source code seems pretty clear in that it only looks
> > > > at the 'im' property:
> >
> > > > Looks like it's time to send-pr.
> >
> > > Thanks Matthew. I did a bit of searching and couldn't find this problem
> > > mentioned anywhere else. I have submitted a PR with id "docs/48018".
> >
> > Ah. Beat me to it. I'm just working up a patch to telnetd to make it
> > work the way the manual says. Just testing now before I submit it.
> >
>
> Oh no, I didn't submit a patch! I just pointed to issue out, suggesting
> that someone may like to remove the incorrect text from the telnetd(8)
> manpage, or possibly update the telnetd sources to match the manpage.
> By all means, please do submit a patch! I do a good bit of work with
> PHP, but I've never programmed with C, so I didn't even think about
> trying to patch. Thanks for all of your help on this issue. This was
> the first PR that I have ever submitted, maybe I shouldn't have
> submitted the PR at all if I didn't have the capability to fix the
> problem. Is there any way that you can send in a patch relating to the
> PR that I already submitted.
Hmmm... Having spent some time looking at this over the weekend, I've
come to the conclusion that adding support for having telnetd display
the /etc/issue file before prompting for a login is impractical when
combined with the SRA encryption used in FreeBSDs standard telnet
setup. It's certainly beyond my extremely rusty C programming skills.
Furthermore, the display of the IM gettytab property is somewhat
dubious as well:
Consider this entry in the standard /etc/gettytab:
default:\
:cb:ce:ck:lc:fd#1000:im=\r\n%s/%m (%h) (%t)\r\n\r\n:sp#1200:\
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
:if=/etc/issue:
which means you should see a banner like:
FreeBSD/i386 (hostname.example.com) (ttyp0)
when you attempt to log in either via telnet or on the console.
However, it's conspicuously absent *before* the login prompt in a
FreeBSD to FreeBSD telnet sesssion:
% telnet localhost
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Trying SRA secure login:
User (matthew):
Password:
[ SRA accepts you ]
FreeBSD/i386 (happy-idiot-talk.infracaninophi) (ttyp4)
Those 'User' and 'Password' prompts originate from the client machine,
and occur as a necessary pre-requisite before the encrypted channel
between the client and server can be set up. So you've got to log in
before you can see any pre-login messages.
I'm not sure what would appear given an older telnet client that
doesn't support encryption, not having any older telnet clients around
to test with.
Cheers,
Matthew
--
Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks
Savill Way
PGP: http://www.infracaninophile.co.uk/pgpkey Marlow
Tel: +44 1628 476614 Bucks., SL7 1TH UK
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