telnetd -Telnet doesnt work

[Chris Fadrowski]

HPUX 11.23 v2 IA64

did some disk work this evening and after reboot telnet does not work. Nothing was touched on the OS disks or vg00 only SAN disk.

how can i stop and start telnetd and troubleshoot this?

[Yogeeraj_1]

hi Chris,

Questions:
1. Can you access the system from the console?

2. has the server properly started? Can you ping the server?


revert

kind regards
yogeeraj

[Chris Fadrowski]

i can get to it thru the console and can use SSH or reflection. just not telnet.

i can ping and have network connectivity. i checked inetd.conf and it appears to have the correct config. Nothing changed here.

i rebooted twice and both times telnet won't work.

[Jeeshan]

Hi Chris

check in /etc/inetd.conf file that telnet line is uncommented.

then run the daemons by command

#inetd -c

[Chris Fadrowski]

the line is uncommented and valid in inetd.conf

i ran inetd -c and nothing happened. Think i need to kill and restart????

[Aashique · Accepted solution]

Hi,
at first connect using ssh.
then check the /etc/inetd.conf

#telnet stream tcp6 nowait root /usr/lbin/telnetd telnetd

is it hash(#)? remove it and then
/usr/sbin/inetd -c


Thanks & Regards

Aashique

[Chris Fadrowski]

i have done this and it doesn't work. Its not commented out. the file looks fine. i killed inetd

how do i restart it?

[Steven Schweda]

What, exactly, does "telnet does not work"
mean? Actual command(s)? Actual error
message(s)?

[Chris Fadrowski]

you try teraterm or a DOS telent and it just closes instantly. If you try it from another unix server it says

Trying...
Connected to hosta.assisted.com.
Escape character is '^]'.
Local flow control off
Connection closed by foreign host.

[Steven Schweda]

Ok. I don't know what the problem is, but
now we can stop blundering around looking for
why the telnetd is not running. It may not
be running properly, but that "Connected to"
message shows that it's running.

Anything informative in the system logs?

[whiteknight]

Chris,

you need to do a basic troubleshooting

such as
#inetd -k
#inetd
#telnet 0
# telnet ip
# nslookup hostname or ip

Hope this help

WK

[Steven Schweda]

> # telnet ip
> # nslookup hostname or ip

I know that he didn't show us the actual
command (as requested), but I was willing to
believe that when it said "Connected to
hosta.assisted.com", he'd notice if that
wasn't the system he was trying to reach.

A problem report with complete info can often
save everyone much wasted time and effort.

[CharlesC]

Might it be someone disabled telnet service as a security measurement? Check the following file:

/var/adm/inetd.sec

[Chris Fadrowski]

did the basics. nslookup from a host shows the server. locally it shows the server.

the issue is telnet is either corrupt or not running. i did the inetd -k, also killed PID and restarted with inetd -c

networking is working and so is DNS.

[Steven Schweda]

> the issue

Is that anything like a _problem_?

> is telnet is either corrupt or not running.

Clearly it's running. "Connected" says that.

Apparently, it's also dying prematurely.

> Anything informative in the system logs?

Could still be interesting.

Have you tried a Google or Forum search for,
say,
telnet "Local flow control off"
? Apparently there are several possible
causes for this symptom.

[Sp4admin]

Hi,

Could there be a firewall rule that is blocking that port from traffic?

sp,

[Steven Schweda]

> Could there be a firewall rule that is
> blocking that port from traffic?

I'm not a firewall expert, but why would a
firewall let the connection happen
("Connected to [...]"), and then abort it?

"man telnetd". Knowing nothing, I'd guess
that the "Local flow control off" message
(which is not normally seen) is related to
the initial options negotiation. Which,
unfortunately, doesn't tell me much about
where to find the problem.

[Sajjad Sahir]

Dear chris

telnet is not working did u checked any other internet services are running ?
like ftp,tftp etc...
if all these are not running
u have to check /etc/rc.config.d/netdaemons file.
and the parameter value if the export_inetd value=0 change in to 1 ok

second thing
if all other services are running like ftp and tftp etc.. except telnet
then u have to check
/etc/inetd.conf file remove # in front of telnet if it is already removed then next step is u have to check /etc/services also
because each interservice is listening a particular port number telnet listening a well known port number 23 see below t
port number of telnet 23/tcp

if any # sign in front of telnet there remove it also from there

and see if u are stoping and starting listen u are using inetd daemon which is a super daemon it controls a lot of internetservice i mean tftp ftp telnet etc... so take care about it

thanks and regards

sajjad

[Bill Hassell]

Always look in /etc/rc.log to see if something went wrong during bootup. Then look in dmesg and finally syslog.log to find some clues. Things like unable to allocate pty, or fork failure or permission denied, etc. telnetd is running because you see the connected message, but as soon as telnet starts the login steps, it fails. This will be logged -- where depends on the type of error, but syslog.log is a best guess.

[Chris Fadrowski]

FTP works and so do the other services under inetd.

No commented out syntax in any of the files;

/etc/services
/etc/inetd.conf
/etc/rc.config.d/netdaemons = export_inetd value=1

all looks good in those files.

only telnet is affected. I have rebooted the server a few times and each time telnet is the only service that is not working. I looked at /etc/rc.log and don't see anything except;

Output from "/sbin/rc2.d/S120swconfig start":
----------------------------
* Turning off all network based resolving services in
'/etc/nsswitch.conf'
* Removing the temporary '/etc/nsswitch.conf'.

/sbin/rc2.d/S131ipfboot: load of /etc/opt/ipf/ipnat.conf failed


from syslog;

Apr 25 00:53:14 yoda vmunix: NOTICE: mod_load_helper: gio_mod_opstart load failed, mcp->mc_typep = 0x81849440

Apr 25 00:54:07 yoda vmunix: NOTICE: mod_load_helper: gio_mod_opstart load failed, mcp->mc_typep = 0x81849440

Apr 25 01:57:34 yoda telnetd[7893]: telnet pty allocation failed
Apr 25 01:58:11 yoda telnetd[7945]: telnet pty allocation failed

[Steven Schweda]

And a search for "telnet pty allocation
failed" didn't lead you to anything useful?

man tels

[Chris Fadrowski]

its obvious that is what is causing it, however, i am trying to get at why... it worked before the last reboot. in fact i telnet to it daily. Just looking for suggestions of why it's failing.

[Steven Schweda]

Too many people using Telnet into that
system? Corrupt device files? Many things
are possible.

[Chris Fadrowski]

i found a fix..

ran insf -e

then /sbin/init.d/inetd stop

then /sbin/init.d/inetd start

and it worked!!!! very odd.

[Steven Schweda]

> [...] very odd.

With no info on the (apparently missing or
defective, now replaced) device files, the
cause may remain a mystery.