Archive for the ‘Troubleshooting’ Category


I am searching nohup.out file in my server. in this case locate command not showing the file but file is available in the system. This is very simple think like very have update system database mean run updatedb.

[root@vm1 ~]# locate nohup.out
/test/nohup.out
/root/nohup.out

[root@vm1 ~]# ll /opt/VMware/bin/nohup.out
-rw——- 1 root root 43539 Jul 16 14:36 /opt/VMware/bin/nohup.out

[root@vm1 ~]# updatedb

[root@vm1 ~]# locate nohup.out
/test/nohup.out
/opt/VMware/bin/nohup.out
/root/nohup.out
[root@vm1 ~]#


Problem

              “REMOTE HOST IDENTIFICATION HAS CHANGED”

 

[root@test ~]# ssh 10.10.10.110

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!

Someone could be eavesdropping on you right now (man-in-the-middle attack)!

It is also possible that a host key has just been changed.

The fingerprint for the ECDSA key sent by the remote host is

SHA256:Z8a5Z9sRzx38HRONwy/jrxt4GeeB8Bb6pGJNTH629bQ.

Please contact your system administrator.

Add correct host key in /root/.ssh/known_hosts to get rid of this message.

Offending ECDSA key in /root/.ssh/known_hosts:1

ECDSA host key for 10.10.10.11 has changed and you have requested strict checking.

Host key verification failed.

#cat /root/.ssh/known_hosts| grep 10.10.10.11

10.10.10.11 ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBCsg9c8VsnZceixYiJ8pq

Reason SSH authentication key is changed in the destination server

Fix for this issue remove or comment older authentication key from source server in /root/.ssh/known_hosts file and try ssh it will work.


[root@test]# ssh 10.10.10.11
ssh_exchange_identification: Connection closed by remote host
Reason for this issue
  •    SSH connection is very slow b/w two clients so not able to exchange the ssh keys #time ssh user@ IP — >figure out why slow
  •    /etc/hosts.deny file may be ssh is added – – > remove the entry
  •    SSH key got corrupted – – > remove the key and exchange new one

  • PXE boot file example

[root@test pxelinux.cfg]# cat test143

default esxi-6
label esxi-6
KERNEL vse/vmware/esxi-hp-600u2/mboot.c32
APPEND -c vse/vmware/esxi-hp-600u2/boot.cfg pxebooting ks=https://xx.xx.xx.xx/builds/hosts/test/test143/ks.cfg noverifyssl ip=xx.xx.xx.xx netmask=xx.xx.xx.xx gateway=xx.xx.xx.xx

 

  • Check PXE boot file below line is correct or wrong in the Linux or vmware server. Modify the correct one and re-try

KERNEL vse/vmware/esxi-hp-600u2/mboot.c32


Possibilities of Gateway is not pining issue

  1. Check Physical connection BW server and switch
  2. Check VLAN id is correct BW server and switch
  3. Check default Firewall rules are disabled or not
  4. Check HW Address && UUID of eth0 interface is correct?
  5. Use correct netmask parameter & netmask IP address should be same.

PREFIX=20
NETMASK=255.255.240.0


Issue :- Windows cannot access samba share 

[test]

path=/backup

what is the problem : – I have created  directory as /BACKUP but i have mentioned  in samba path as /backup so here samba share path is not correct hence i getting below error

FIX : – Modify correct share directory name and restart samba service it will work.


Problem  : – samba is not accessible. you might not have permission to use this network resource

why it happens: –  Windows machine still pointing older samba shares hence you got above issue . Need to be clear the samba cache

FIX :-  Need to be clear the samba cache

Open command line console (menu start -> run -> cmd (ctrl + shift +enter will open with Administrator privileges))
>net use
>net use \\address_ip\share /delete
eg.
>net use \\192.168.1.1\photos /delete