From and OPSEC stand point man, you probably shouldn't have replied to that email... Replying makes it easier for some one with some know how to accuire your IP and such. Since you are on a military domain, that type of info would be usefull to the "sheet head" types to defeat the network security programs. If you recieve any more emails of that nature on you gov. email, don't reply. Report it to your Sq CSA, ISSO, or immidiate supervisor so they can determine what the persons intentions were and possible launch a OSI investigation if there is cause.