topic Re: Telnet problem in Operating System - HP-UX

Telnet problem

prakasse — Thu, 13 Sep 2007 00:37:47 GMT

Hi,

I face this problem on Itanium rx2620 with HP-UX 11.23

Here are the symptons:

1. Error message in /var/adm/syslog/syslog.log file:
hprx2620 telnetd[5134]: telnet pty allocation failed

2. telnet from solaris machine:
bv-nis:root:[223] telnet hprx2620
Trying 10.10.102.68...
Connected to hprx2620.
Escape character is '^]'.
Connection closed by foreign host.

3. telnet from hp-ux machine:
# telnet hprx2620
Trying...
Connected to hprx2620.broadvision.com.
Escape character is '^]'.
Local flow control off
Connection closed by foreign host.

4. telnet from windows' dos command line: no reponse

Could you please help us to solve this problem? Is it something to do with pty allocation?

Thanks in advance,
Senthil

Re: Telnet problem

whiteknight — Thu, 13 Sep 2007 00:53:34 GMT

hi Parkasse,

firstly check you have patch up telnetd

PHNE_35770 11.23 telnet kernel, telnetd(1M), telnet(1) patch

Step 1: Find out the value of the kernel parameter nstrtel which is what
controls the maximum number of telnet sessions in conjunction with the "tels"
device files:
# kmtune -q nstrtel
Parameter Current Dyn Planned Module Version
===============================================================================
nstrtel 60 - 60

Step 2: Find out how many "tels" device files are available, which also
control the maximum number of telnet sessions. They are found in /dev/pts and
begin with the letter "t":
# ls /dev/pts/t* | wc -w
60

If the kernel parameter is already at your desired value, but you don't have
enough device files, skip to Step 5.

Step 3: Run SAM to modify the kernel parameter:
Use SAM
Kernel
Configurable Parameters
nstrtel
Set nstrtel to your desired value, e.g. 512, save and reboot.

Step 4: Upon reboot, repeat Step #1 to verify the nstrtel kernal parameter is
at your desired value.

Step 5: Build the desired number of the "tels" device files. There are
several ways to do this. Use -s to specify the number of device files to
build:
# insf -d tels -s 512

Note: Existing device files are not recreated unless you delete them. The -e
parameter does not recreate them in contrast of what the insf man page
states.

Step 6: Repeat Step #2 to verify you have the number of device files desired.

For more detailed technical information:
See tels(7) and telm(7) man page for details of the telnet device files.

Also please note the following:
The npty kernel parameter does not control nor affect telnet sessions. That
parameter affects pty's used for non-telnet and non-r-command purposes, such
as hpterm and xterm ptys. See pty(7).

The nstrpty kernel parameter controls r-command and secure shell pty's
called "pts". See pts (7) and ptm(7). Device files in /dev/pts that start
with a number are used by the "r-commands" such as rlogin.

The telnet master pty is /dev/telnetm. There is only one. If it is missing,
it can be recreated as follows:
# insf -d telm -e -v
insf: Installing special files for pseudo driver telm
making telnetm c 72 0x000020

WK
please assign points

Re: Telnet problem

Aneesh Mohan — Thu, 13 Sep 2007 01:50:04 GMT

Check the number of pty/s drivers that are created in /dev/pty and /dev/pts

# ls *|wc -l

Increase the count to say 200
# cd /dev
# insf -n200 -dpty0
# insf -n200 -dpty1
# insf -d pts -s 200 -e
c) Now try to login again

if it not solved change the below kernel values to bigger value say 400 (Reboot required )

nstrtel
npty
nstrpty

Re: Telnet problem

prakasse — Fri, 14 Sep 2007 01:56:34 GMT

Hi,

Thank you for your quick response and instruction.

I downloaded patch PHNE_35770 and its required patches, and installed them
on our server.

But telnet still does not work after rebooting the server.

Then I used swlist -l patch | grep PHNE_35770 command, and got the following
result:

# swlist -l patch| grep PHNE_35770
PHNE_35770.INET-ENG-A-MAN 1.0
InternetSrvcs.INET-ENG-A-MA
N applied
PHNE_35770.INETSVCS2-RUN 1.0
InternetSrvcs.INETSVCS2-RUN
applied
PHNE_35770.NET2-KRN 1.0 Networking.NET2-KRN applied

PHNE_35770.KERN-ENG-A-MAN 1.0 OS-Core.KERN-ENG-A-MAN
a
pplied
# PHNE_35770 1.0 telnet kernel,
telnetd(1M
), telnet(1) patch
# PHNE_35770.INET-ENG-A-MAN 1.0
InternetSrvcs.INET-
ENG-A-MAN applied
# PHNE_35770.INETSVCS2-RUN 1.0
InternetSrvcs.INETS
VCS2-RUN applied
# PHNE_35770.KERN-ENG-A-MAN 1.0
OS-Core.KERN-ENG-A-
MAN applied
# PHNE_35770.NET2-KRN 1.0
Networking.NET2-KRN
applied

Could you help me to figure out what could be wrong? Why # sign infront of
PHNE_35770?

Further info:

# uname -a
HP-UX hprx2620 B.11.23 U ia64 0169430382 unlimited-user license
# kmtune -q nstrtel kmtune is a wrapper script which exists for compatibility reasons only.
The underlying command used is 'kctune'. New or modified scripts or procedures should use kctune directly.
About to execute:
kctune -q nstrtel
Tunable Value Expression
nstrtel 60 Default
# ls /dev/pts/t* | wc -w
60

Right now I am the only user to access the server. I think we may need around 10 telnet/rlogin/ssh session for development later on.

Thanks in advance,
Senthil.