Python script to check valid email addresses

We were having discussion about checking a list of email addresses for validity.
one of member had posted a bash script for Linux to verify the email addresses before sending the emails.

I thought to write a python script for the same in windows. Well this script can be easily ported to linux with just one or two lines changed. But I was too tired after all day office work to write check for OS and write windows as well as linux code. Currently it is only for gmail domain. But can be easily ported to every domain. Just need to extract domain from email id and check its MX by the existing code. (I told you already I am tired to write more code)
If some people found this useful and need sophisticated version then I would release a next version of program.

This python code take one argument which is list of emails one per line in text format.

You can download python file HERE

How to implement Proxy ARP on linux box

Note If you dont know what is proxy arp then stop reading this
and read this first http://en.wikipedia.org/wiki/Proxy_arp

The scenario before implementation of Proxy ARP is as bellow (Before Proxy ARP)
There is a server (10.10.10.3) on the LAN (10.10.10.0/24) that
we want to put in to DMZ. But normally if we move the server we
have to change its ip address and put it into different lan network
But by using proxy arp we can port the server to DMZ without changing
any configuration like ip address.

Before proxy ARP

         |
         | eth1
     +-------+
     |Linux  |-- eth2
     |Box    |
     +-------+
        |
        | eth0
        | 10.10.10.0/24
        |
----|---|--------|----------
    |            | 
   10.10.10.3   10.10.10.?
    Server

After implementation of the Proxy arp we can put the Server directly connected to eth2
without changing its ip address.

To implement proxy ARP following steps should be followed

1.Turn on the proxy ARP option on the selected interfaces
To do this we have to put value 1 in to the proc file.

echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp
echo 1 > /proc/sys/net/ipv4/conf/eth2/proxy_arp

2. Delete Route of LAN from eth0

route del -net 10.10.10.0 netmask 255.255.255.0 dev eth0

3. Add Routes for proxy ARP

route add 10.10.10.3 dev eth0
route add -net 10.10.10.0 netmask 255.255.255.0 dev eth0

Now the Proxy ARP is working and the Systems in the LAN (10.10.10.0/24) will
be able to communicate with server (10.10.10.3) similar to what that was before
proxy arp. Now you can put the iptables rules to prevent/allow access the server if you want.

After Proxy ARP

        |
        | eth1
    +-------+
    |Linux  |------- 10.10.10.3
    |Box    | eth2
    +-------+
        |
        | eth0
        | 10.10.10.0/24
        |
----|---|--------|----
    |            |