Inter VLAN routing with linux

https://thejimmahknows.com/inter-vlan-routing-with-linux-powerconnect-5324/

http://parkersamp.com/2010/03/howto-using-linux-as-a-simple-load-balancer-nat-router-firewall/

squid install guide on windows

never tried

http://certcollection.org/forum/topic/98920-installing-squid-proxy-server-running-on-windows/

Fix yum error CentOS linux : Error: file is encrypted or is not a database

Error: file is encrypted or is not a database             

[sameera@gemini test2]$ sudo yum clean
Loaded plugins: fastestmirror, refresh-packagekit, security
Error: clean requires an option: headers, packages, metadata, dbcache, plugins, expire-cache, rpmdb, all
[sameera@gemini test2]$ sudo yum clean all
Loaded plugins: fastestmirror, refresh-packagekit, security
Cleaning repos: base epel extras linuxtech-release rpmforge updates
Cleaning up Everything

PPTP VPN server Linux

Step 1. Install PPTPD
If your OS is CentOS/RedHat 5:

yum install ppp
cd /usr/local/src
wget http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-2.rhel5.x86_64.rpm
rpm -Uhv pptpd-1.3.4-2.rhel5.x86_64.rpm

If your OS is CentOS/RedHat 6:

yum install ppp
cd /usr/local/src
wget http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-2.el6.x86_64.rpm
rpm -Uhv pptpd-1.3.4-2.el6.x86_64.rpm

If you are using Ubuntu:

apt-get install pptpd

Step 2. Edit IP setttings in /etc/pptpd.conf
vi /etc/pptpd.conf

localip 192.168.0.1
remoteip 192.168.0.101-200

Step 3. Add user account in/etc/ppp/chap-secrets (assign username and password)
vi /etc/ppp/chap-secrets

usernameForuser1 *  setpassword1here  *
usernameForuser2 *  setpassword2here  *

Step 4. Optional settings in /etc/ppp/options.pptpd
vi /etc/ppp/options.pptpd

ms-dns 8.8.8.8
ms-dns 4.4.4.4

Step 5. Enable network forwarding in /etc/sysctl.conf
vi /etc/sysctl.conf

net.ipv4.ip_forward = 1

use the following command to apply the change:
sysctl -p
Step 6. Configure firewall
iptables -A INPUT -i eth0 -p tcp --dport 1723 -j ACCEPT
iptables -A INPUT -i eth0 -p gre -j ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -A FORWARD -i ppp+ -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o ppp+ -j ACCEPT
service iptables save
service iptables restart
If you are using CSF firewall, you may refer to this post on firewall settings.
Step 7. Start PPTP VPN server
If your OS is CentOS or Redhat, using the following command:
service pptpd restart

To start PPTP Daemon automatically when rebooting next time, use command:

chkconfig pptpd on

If your OS is Ubuntu, you just reboot your machine.
Now you can test the VPN server from any client: Windows PCs, Linux PCs, Android phones/tablets, or iPhone and iPad.
The log of the VPN server, by default, is combined with system log located at /var/log/messages.

Removing AD Domain Controller  by  Force

use   dcpromo /forceremoval  command

How to recover cisco switch port from err-disable state

Port is in err-disable state? And you don't know what to do?

switch01#show int G1/0/19
GigabitEthernet1/0/19 is down, line protocol is down (err-disabled)

Find out the main reason for err-disable state. In our case it is port security violation on port Gi1/0/19.

#show interfaces status err-disabled
Port      Name               Status       Reason
Gi1/0/19  SERVER01    err-disabled psecure-violation
Gi1/0/46                     err-disabled psecure-violation
Gi2/0/12                     err-disabled psecure-violation

Fix port configuration:

int G1/0/19
 no switchport port-security
 shut
 no shut

activate windows 7 command line

1. Open up an elevated command prompt.
2. Enter the following

   slmgr -ipk your-mak-key-here
   
   slmgr -ato