issues using nslookup to authenticate an e-mail address
Posted on 2003-04-01
I have a number of mail forms on my site, with the user's e-mail address a required field. For years I've used nslookup to authenticate the user's e-mail before I sent the comment off to my company. I did this by running the following script (more or less):
And then searching the return string for the string "mail exchanger." This has proved a reliable technique, until I found a valid domain that does not return "mail exchanger." It does, however, return "responsible mail addr."
Does the presence of "responsible mail addr" in the nslookup return string guarantee valid e-mail?
If not, what does?