Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!
cannot ssh to a centOS 4.9 server
I have an old centOS 4.9 Server. I cannot ssh to it.
it's a vmware server, I can use console to log into the server as root. I checked the sshd service, it's on, I checked the iptables service, it's off.
I checked the .ssh folder under root and can only find one file called known_hosts. no other files found under the same folder, even no config file.
anyone can help me with this,thanks.
it's a vmware server, I can use console to log into the server as root. I checked the sshd service, it's on, I checked the iptables service, it's off.
I checked the .ssh folder under root and can only find one file called known_hosts. no other files found under the same folder, even no config file.
anyone can help me with this,thanks.
Do more with
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®
try to stop the selinux and login
check any PAM related files are updated
can you paste the logs when you are trying to ssh from remove
try this on the vmware console
tail -f /var/log/messages
check any PAM related files are updated
can you paste the logs when you are trying to ssh from remove
try this on the vmware console
tail -f /var/log/messages
also check what port the SSH is running from?
Check the file /etc/ssh/sshd_config and check for Port.
As suggested by Shiju above also check the selinux.
Verify the port which is set on sshd_config is configured on Firewall as well.
Sudeep
Check the file /etc/ssh/sshd_config and check for Port.
As suggested by Shiju above also check the selinux.
Verify the port which is set on sshd_config is configured on Firewall as well.
Sudeep
Are you trying to log in as root or a user??
Check service is running:
service sshd status
Check iptables allows connections:
iptables -L -vn | grep "dpt:22"
Check if root is allowed to log in per config:
grep -i permitrootlogin /etc/ssh/sshd_config
Check if config allows password authentication:
grep PasswordAuthentication /etc/ssh/sshd_config
Check service is running:
service sshd status
Check iptables allows connections:
iptables -L -vn | grep "dpt:22"
Check if root is allowed to log in per config:
grep -i permitrootlogin /etc/ssh/sshd_config
Check if config allows password authentication:
grep PasswordAuthentication /etc/ssh/sshd_config
This is the content of the ssh_config file:
# $OpenBSD: ssh_config,v 1.19 2003/08/13 08:46:31 markus Exp $
# This is the ssh client system-wide configuration file. See
# ssh_config(5) for more information. This file provides defaults for
# users, and the values can be changed in per-user configuration files
# or on the command line.
# Configuration data is parsed as follows:
# 1. command line options
# 2. user-specific file
# 3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.
# Site-wide defaults for various options
# Host *
# ForwardAgent no
# ForwardX11 no
# RhostsRSAAuthentication no
# RSAAuthentication yes
PasswordAuthentication yes
# HostbasedAuthentication no
# BatchMode no
# CheckHostIP yes
# AddressFamily any
# ConnectTimeout 0
# StrictHostKeyChecking ask
# IdentityFile ~/.ssh/identity
# IdentityFile ~/.ssh/id_rsa
# IdentityFile ~/.ssh/id_dsa
Port 22
Protocol 2,1
# Cipher 3des
# Ciphers aes128-cbc,3des-cbc,blowfi
# EscapeChar ~
Host *
GSSAPIAuthentication yes
# If this option is set to yes then the remote X11 clients will have full access
# to the local X11 display. As virtually no X11 client supports the untrusted
# mode correctly we set this to yes.
ForwardX11Trusted yes
# $OpenBSD: ssh_config,v 1.19 2003/08/13 08:46:31 markus Exp $
# This is the ssh client system-wide configuration file. See
# ssh_config(5) for more information. This file provides defaults for
# users, and the values can be changed in per-user configuration files
# or on the command line.
# Configuration data is parsed as follows:
# 1. command line options
# 2. user-specific file
# 3. system-wide file
# Any configuration value is only changed the first time it is set.
# Thus, host-specific definitions should be at the beginning of the
# configuration file, and defaults at the end.
# Site-wide defaults for various options
# Host *
# ForwardAgent no
# ForwardX11 no
# RhostsRSAAuthentication no
# RSAAuthentication yes
PasswordAuthentication yes
# HostbasedAuthentication no
# BatchMode no
# CheckHostIP yes
# AddressFamily any
# ConnectTimeout 0
# StrictHostKeyChecking ask
# IdentityFile ~/.ssh/identity
# IdentityFile ~/.ssh/id_rsa
# IdentityFile ~/.ssh/id_dsa
Port 22
Protocol 2,1
# Cipher 3des
# Ciphers aes128-cbc,3des-cbc,blowfi
# EscapeChar ~
Host *
GSSAPIAuthentication yes
# If this option is set to yes then the remote X11 clients will have full access
# to the local X11 display. As virtually no X11 client supports the untrusted
# mode correctly we set this to yes.
ForwardX11Trusted yes
I checked both files, there are nothing in there.
Do I need add my ip in, if so, what is the format?
thanks.
Do I need add my ip in, if so, what is the format?
thanks.
nope, if they are blank thats cool, they can also be used to restrict access to services most people forget about them.
Looking at your posts above it might be you have a bad entry in pam. Check out the log files again;
/var/log/secure
/var/log/messages
/var/log/audit/audit.log
Looking at your posts above it might be you have a bad entry in pam. Check out the log files again;
/var/log/secure
/var/log/messages
/var/log/audit/audit.log
in this file : /var/log/messages
There are many lines as below:
PAM-Cracklib[9775]: pam_parse: unknown option; reject_username.
Is there something with my pam_parse module?
Please advise.
There are many lines as below:
PAM-Cracklib[9775]: pam_parse: unknown option; reject_username.
Is there something with my pam_parse module?
Please advise.
I think maybe the pam modules under /etc/pam.d need to be modified.
Please see the copy scrren for the file /etc/pam.d/sshd .
pam-picture2.png
Please see the copy scrren for the file /etc/pam.d/sshd .
pam-picture2.png
I dont think its that file, it might be in login or system-auth.
Unfortunately I dont have a CentOS 4.9 box I can use to check PAM.
Can you verify the pam package?
Unfortunately I dont have a CentOS 4.9 box I can use to check PAM.
Can you verify the pam package?
rpm -V pam
ls -altr /etc/pam.d
I'm assuming it does local auth as well and you dont have some strange network auth setup, try running
It should tell you what its expecting, check the man page for details.
authconfig --test
It should tell you what its expecting, check the man page for details.
here are the results. Unfortunately, I couldn't copy and paste the result to here, have to use the copy screen from vmware console.
ssh3.JPG
pam-picture4.png
pam-picture3.png
ssh3.JPG
pam-picture4.png
pam-picture3.png
system-auth was modified which is fine if thats what you needed for your setup but its worth having a look
how to test to bypass the system-auth file?
I want to first identify the problem, then consider how to resolve it.
Here I am attaching the detail of this system-auth file for your scrutinization.
system--001.png
system-002.png
I want to first identify the problem, then consider how to resolve it.
Here I am attaching the detail of this system-auth file for your scrutinization.
system--001.png
system-002.png
line 14, put a # at the start and save it, then try and ssh in
open another console window and try and login locally too or use ssh localhost in the console
open another console window and try and login locally too or use ssh localhost in the console
after I modified this system-auth file and run ssh localhost as root, it shows "Permission denied, please try again.
please see the copy screen.
new.png
please see the copy screen.
new.png
ok, put the cracklib line back but just remove the reject_username so it reads;
password requisite /lib/security/$ISA/pam_cracklib.so retry=3 minlen=8 minclass=3
I tried to catch the log from /var/log/secure and found the following lines when tried to login
Failed password for jasony from ::ffff:172.16.49.115 port 53389 ssh2
login-error.png
Failed password for jasony from ::ffff:172.16.49.115 port 53389 ssh2
login-error.png
I checked the secure file, it keep saying "Failed password for myusername from ::ffff:XXX.XXX.XXX.XXX(my desktop IP) port 54043 ssh2.
Please see the copy screen.
logon-error-2.png
Please see the copy screen.
logon-error-2.png
I just reset the password for my username. but when I ssh to the server, it still says "access denied".
from the /var/log/secure file, it shows:
Failed password for jasony from ::ffff:my ip port 60157 ssh2.
The port number is different every time I tried to login.
thanks.
from the /var/log/secure file, it shows:
Failed password for jasony from ::ffff:my ip port 60157 ssh2.
The port number is different every time I tried to login.
thanks.
Is it doing local auth? can you post the output to authconfig --test as mentioned above.
The port number mentioned in the log is the source port which varies so thats ok.
The port number mentioned in the log is the source port which varies so thats ok.
what do you mean by usering authconfig --test?
How to use it for test?
I tried to run "ssh -vvv localhost" and get the following error as it showed in the attachment.
error-003.png
error-004.png
How to use it for test?
I tried to run "ssh -vvv localhost" and get the following error as it showed in the attachment.
error-003.png
error-004.png
it uses kerberos....
do you need that?
I'm not suggesting you change it as it might affect your security policy.
running authconfig --test should have displayed printed output,
do you need that?
I'm not suggesting you change it as it might affect your security policy.
running authconfig --test should have displayed printed output,
if you want to test it without then save a copy of the auth files in pam and make notes of the settings then (only if you are allowed) change the setting to disable kerberos and try that, if you can then login you now know where to look and you should involve your security team if you have one.
Alas I dont know much about kerberos.. :-D
Alas I dont know much about kerberos.. :-D
What is this Kerberos authentication? Is the settings for Kerberos crashed?
How can I use SSH with Kerberos? Or I need disable Kerberos to use SSH, please advise.
Thanks in advance.
How can I use SSH with Kerberos? Or I need disable Kerberos to use SSH, please advise.
Thanks in advance.
After I disabled Kerberos, it's still not working.
The error message is the same in /var/log/secure file.
thanks.
The error message is the same in /var/log/secure file.
thanks.
kerberos needs an external server for auth as far as I know. Can you post your authconfig again please.
we need to be sure its disabled.
Is there any possibility in showing more of the secure file and is there anything in messages?
we need to be sure its disabled.
Is there any possibility in showing more of the secure file and is there anything in messages?
I just build a 4.8 vm and the system-auth file on a base install looks like this;
#%PAM-1.0
# This file is auto-generated.
# User changes will be destroyed the next time authconfig is run.
auth required /lib/security/$ISA/pam_env.so
auth sufficient /lib/security/$ISA/pam_unix.so likeauth nullok
auth required /lib/security/$ISA/pam_deny.so
account required /lib/security/$ISA/pam_unix.so
account sufficient /lib/security/$ISA/pam_succeed_if.so uid < 100 quiet
account required /lib/security/$ISA/pam_permit.so
password requisite /lib/security/$ISA/pam_cracklib.so retry=3
password sufficient /lib/security/$ISA/pam_unix.so nullok use_authtok md5
shadow
password required /lib/security/$ISA/pam_deny.so
session required /lib/security/$ISA/pam_limits.so
session required /lib/security/$ISA/pam_unix.so
The KerberoAuthenticsation is enabled.
Please see the attached copy screen from the file /etc/ssh/sshd_config.
I will copy the secure file and message file later.
kerberos-enabled.png
Please see the attached copy screen from the file /etc/ssh/sshd_config.
I will copy the secure file and message file later.
kerberos-enabled.png
Here are the copy screens of the command "authconfig --test". I talked to my coworkers, they said this server is integrated with Active directory for authentication. From the second copy screen, you can see a domain controller's name.
authconfig-001.png
authconfig--002.png
authconfig-001.png
authconfig--002.png
ok, well I'm guessing thats why you cant login, you should try to disable the kerberos stuff and then make sure you can login from the local network before looking to re-enable it..
I got a new problem right now, I cannot use root user to login from the console, it says root user is locked. I have to use my own account to login from the console ans su to root.
Premium Content
You need an Expert Office subscription to comment.Start Free Trial