telnet

[navin]

Hi i have a server (virtual machine) ..can not seem to telnet to that box.But ssh works fine.Once i launch telnet window ...it just stays there instead of proving the login prompt.
any idea? .Thanks much

[A. Clay Stephenson]

Normally when ssh is installed on a box, telnet and "vanilla" ftp are disabled otherwise the benefits of ssh/sftp are largely lost. Have a look at your /etc/inetd.conf file and see if the telnet entry is missing or commented out. To re-establish the service, find the commented line; remove the comment; and save the file. You must then issue an "inetd -c" command to send a SIGHUP to inetd so that if will reconfigure itself.

[Steven Schweda]

Is this yet another case where a reverse
(address-to-name) DNS look-up fails/hangs?

If SSH works, log in that way, and see if
"nslookup " works. If
not, add the client system to /etc/hosts, or
else fix the DNS problem.

[navin]

Thanks so much for the reply.I have checked the suggestions(Thank you) , but same issues.Please advice..

[Ivan Krastev]

Hi navin,

Check for telnet daemon - try 'telnet localhost' after logging on server to be sure that everything is ok. Check also for existing (hung) telnetd daemons and kill them if its necessary.



regards,
ivan

[skt_skt]

login though ssh.

check "telnet hostnameORip 23"


you might have a entry like this in /etc/services

telnet 23/tcp # Virtual Terminal Protocol

[Tor-Arne Nostdal]

Hi navin
you don't mention what kind of "box"... or OS that is running.
Since you post in this forum - we must assume it is HP-UX. You do not mention what version it run or if this system is hardened in any way... Normally telnet would be enabled by default.
Have this problem suddenly arised?

Could there be a firewall that blocks you?
the "loopback" test proposed by Ivan should identify this.

Telnet is invoked by inetd. The configuration of inetd is done in /etc/inetd.conf
example:
telnet stream tcp6 nowait root /usr/lbin/telnetd telnetd
Check that the program really exist:
ll /usr/lbin/telnetd

If you telnet to a machine without any parameters, the default port would be 23
The link between port numbers and inetd services is defined in file /etc/services
Check that your telnet application really uses port 23, and that your server really uses this port:
grep telnet /etc/services
telnet 23/tcp # Virtual Terminal Protocol

Remember - your system might be hardened (mentioned by Clay). You might need to check out f.ex. the inetd.sec
see: man inetd.sec

See also: http://forums1.itrc.hp.com/service/forums/helptips.do?#33

/Tor-Arne

[shardam]

Hi Navin,

Check the /var/adm/inetd.sec whether there's any entry of DENY for your hosts/ip/subnets where you use to telnet session. Or else, if you implemented with tcp wrapper for telnet there might be some restriction also set in hosts.allow/deny file in /etc. You may check if this was implemented by looking from the entry of /etc/inetd.conf:

telnet stream tcp nowait root /usr/lbin/tcpd /usr/lbin/telnetd telnetd