mx record lookup command line
If your site is connected to the Internet, you can use the nslookup (1) program to interactively find MX and other records. To run nslookup , just type its name:
%
nslookup
Note that you may have to give the full pathname. Under SunOS, nslookup lives in the /usr/etc directory; under Ultrix, in /usr/ucb ; and under HP-UX, in /usr/bin .