#!/bin/bash
# check_mail_servers
#   A lame way to check what mail servers people run

# Read from the uni list and run host to find the mail servers
for company in `cat ./companies`
do
    /usr/bin/host -t MX $company | head -n1 >> ./host_output
done 

# Get the server names into a file
/bin/cat ./host_output | /bin/cut -d" " -f7 > ./mail_servers

# Connect to each, pull its banner, then disconect
for server in `cat ./mail_servers`
do
   /bin/nc -w5 $server 25 < ./netcat_input >> ./server_strings
done

# Get just the initial response from the server
/bin/grep 220 server_strings > ./server_strings_refined

# Get everyting else
/bin/grep -v 220 server_strings > ./server_strings_chatter

# Cleanup
/bin/mv ./host_output ./old_host_output
/bin/mv ./server_strings ./orig_server_strings