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Enable the command-line talk program UNIX
You can let other users connected to your machine via SSH chat with you and each other using the Terminal. This gives you convenience of real time dialog over a highly secure connection (and faster then various flooded chat networks).

It can be done via talk,a program installed under BSD but disabled by default. All you need is to change the inetd configuration database file:
 % sudo pico /etc/inetd.conf
Uncomment the "ntalk" line:
 ntalk dgram udp wait root /usr/libexec/tcpd ntalkd
After rebooting, to chat with a user connected to the same machine, just type:
 % talk [username]
Refer to the very easy talk manual ("man talk") to find out more details. Hope this helps...

[Editor's note: I thought I had read about various security holes in the "ntalk" server, and that's why it was disabled by default -- does anyone have more information on this subject?]
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ntalkd
Authored by: tsaar on Jul 17, '02 02:31:01AM

Talkd /Ntalkd supposedly has its security issues (but I would not know how serious these are)

The whole point of talk ofcourse is that you can talk to a remote user on a remote machine: talk mybuddy@mybuddyscomputer.net
No need to login to mybuddyscomputer.net. (for instance, when your buddy thinks giving you a shell account on his machine is a big risk ;) )
Also see finger (remember the .plan file?)

Many people have been trying to get _this_ normal, remote (as opposed to talking to users on your own machine) funcionality working also.
I'm not sure, but I believe there's a thread on Apple's own discussion forums about this. I seem to remember they weren't very succesfull.

Doei,
Maarten



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ntalkd
Authored by: tsaar on Jul 17, '02 11:36:29AM
Check out this thread (macosx.com, is it allright if I link there?) for more details. doei.

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ntalkd
Authored by: strider on Jul 17, '02 02:04:06PM

The remote aspect of ntalk does represent a security risk. However, if you only use it as the original poster suggested (ie only talk to people SSH'd into your local machine), just make sure that UDP 517 is allowed from 127.0.0.1 to 127.0.0.1 and not from the internet. You are running a firewall right? Someone would have to have have shell access to your box to exploit talk and at that point you have bigger problems than running talk :)



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ntalkd
Authored by: jitjat on Jan 13, '03 09:15:01PM

I believe older versions of talkd didn't check for ;'s in domain names and used system commands. In theory, someone could talk to a machine and pass commands after the ;. Since talkd runs under root, damage could be done.

I don't know if the ntalkd that comes with OS X has fixed this problem but I am fairly certain that it was fixed in FreeBSD...



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Enable the command-line talk program
Authored by: swimp on Aug 29, '03 04:10:04PM

hey, Do you guys know how to enable this on Gentoo Linux?



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Comments from anonymous
Authored by: robg on Oct 15, '03 10:00:33AM
A reader sent this in as a new hint, but it really belongs here as a related comment:
mici stated that after you uncomment the ntalk line in then inetd.conf file, you must restart the machine.

I have another way to open the port that inetd listens for talk. Following this you won't have to restart the machine to enable talk.
[cbaldwin@MoonUnit1 ~] $ ps -auxw | grep inetd
root       411   0.0  0.0     1308    108  ??  Ss   Sat01AM   0:00.01 inetd
root       414   0.0  0.0     1480    260  ??  Ss   Sat01AM   0:00.03 xinetd -pidfile /var/run/xinetd.pid
This will give you the Process ID or pid. In this case it is 411. Now just type sudo kill -HUP 411 and enter your admin password when prompted. Talk is now enabled without a restart.

Hope this is helpful.

Corey Baldwin
-rob.

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Enable the command-line talk program
Authored by: cryptlib on Apr 15, '04 06:02:09PM

To enable talk, I just uncommented "ntalk" from /etc/inetd.conf, and perhaps rebooted or sent something a hangup signal. I'm not so worried about the security of doing this, 'cause I have a little Netgear natbox/firewall preventing anyone from connecting to the talk port from outside my home network, and I trust my honey to use Ssh responsibly.

---
% kill -H -1



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