How to update Centos 5 .X and cannot find a valid baseurl for repo
If you are using CentOS 5.x and want to install any software and update CentOS 5.x . you are getting following error .
root@server1 [~]# yum update -y
Loaded plugins: fastestmirror
Determining fastest mirrors
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/
removing mirrorlist with no valid mirrors: /var/cache/yum/base/mirrorlist.txt
Error: Cannot find a valid baseurl for repo: base
This is because update repositories were moved to the CentOS vault when the operating reached it's end-of-life.
Edit the following file
Continue reading How to update Centos 5 .X and cannot find a valid baseurl for repo
vos3000 illegal calls query to block IP address
All call records are saved in e_cdr_files
you can query to get ip addresses of illegal calls source.
mysql> select DISTINCT callerip from e_cdr_20180818 where endreason = ‘-9’;
| callerip |
| 220.127.116.11 |
| 18.104.22.168 |
| 22.214.171.124 |
| 126.96.36.199 |
| 188.8.131.52 |
| 184.108.40.206 |
| 220.127.116.11 |
| 18.104.22.168 |
| 22.214.171.124 |
| 126.96.36.199 |
10 rows in set (0.00 sec)
if someone can write a script to get IP address from current date CDR for every 5 min and update the iptables automatically.
How to configure Mikrotik DHCP Server for Cisco Phone TFTP option
1- Change your TFTP server IP in to hex code
you can use this online tool : http://www.miniwebtool.com/ip-address-to-hex-converter/
2- Now configure Mikrotik RouterOS :
/ip dhcp-server option add code=150 name=ciscotftp value=0xC0A80307
Continue reading How to configure Mikrotik DHCP Server for Cisco Phone TFTP option
How to install VMware tools in Linux Virtual Machine
- Make sure Linux virtual machine is powered on.
- Click VMin the virtual machine menu, then click Guest > Install/Upgrade VMware Tools.
- Click OK.Note: In some cases, verify that the CDROM device is Connectedfrom within the Edit Settings option of the virtual machine.
- To create a mount point, run:mkdir /mnt/cdrom
- To mount the CDROM, run:mount /dev/cdrom /mnt/cdrom
Continue reading How to install VMware tools in Linux Virtual Machine
OpenVPN CRL has expired
VERIFY ERROR: depth=0, error=CRL has expired: CN=servername
In order to fix the issue, we just need to recreate the crl.pem file.
we need to backup the current crl.pem file before creating a new one.
The location of the crl.pem file at /etc/openvpn/
#mv crl.pem crl.pem.back
Now go to easy-rsa folder
# cd easy-rsa
now generate crl.pem
# ./easyrsa gen–crl
Now copy the new crl.pem to openvpn folder
# cp –pr /etc/openvpn/easy–rsa/pki/crl.pem
Now restart openvpn service
source link :- https://www.jobishmathew.me/openvpn-crl-has-expired/
To troubleshoot connection issues check below logs
grep the client name in /var/log/messages
# grep VPN /var/log/messages
Check the connection time
Check the connection negotiation activity
# tail -f /var/log/messages
How to install vos3000 188.8.131.52 on CentOS 6.X
Follow the steps
#chkconfig iptables off
#chkconfig ip6tables off
Continue reading How to install vos3000 184.108.40.206 on CentOS 6.X
VMware OS Optimization Tool
The VMware OS Optimization Tool helps optimize Windows 7/8/2008/2012/10 systems for use with VMware Horizon View. The optimization tool includes customizable templates to enable or disable Windows system services and features, per VMware recommendations and best practices, across multiple systems. Since most Windows system services are enabled by default, the optimization tool can be used to easily disable unnecessary services and features to improve performance.
You can perform the following actions using the VMware OS Optimization Tool:
- Local Analyze/Optimize
- Remote Analyze
- Optimization History and Rollback
- Managing Templates
Download latest VMware OS Optimization Tool
SSH Login Email Alerts
The examples below send an email when someone logs into your server. For this to work, your server must be able to send mail using the
Open the file
~/.bash_profile in a text editor.
Append the following lines:
IP="$(echo $SSH_CONNECTION | cut -d " " -f 1)"
NOW=$(date +"%e %b %Y, %a %r")
echo 'Someone from '$IP' logged into '$HOSTNAME' on '$NOW'.' | mail -s 'SSH Login Notification' YOUR_EMAIL_ADDRESS
iptables port forwarding
I am port forwarding public ip x.x.x.x to private ip 192.168.200.200 .
iptables -A INPUT -i eth0 -p tcp –dport 5001 -m state –state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp –sport 5001 -m state –state ESTABLISHED -j ACCEPT
iptables -t nat -A PREROUTING -i eth0 -p tcp -m tcp –dport 5001 -j DNAT –to-destination 192.168.200.200:5001
Continue reading iptables port forwarding