samwyse has asked for the wisdom of the Perl Monks concerning the following question:
Back in the day, I could telnet to my local SMTP server and easily forge emails, to the amazement of my friends and colleagues. This week, I'm trying to get a web service to send an email verification email, and nothing is working. Right now, I'm using my laptop, and I've tried while both on and off my company's network, connecting to the server specified in my Exchange settings, my company's public MX record, and my home ISP's MX record. For all three, Net::SMTP returns undef, with no messages despite having debug tuned on, Mail::Sendmail is the same, and I can't even connect using telnet to port 23. For what it's worth, my Exchange server settings include "Logon network security: Negotiate Authentication". And while I'll be asking my company's IT staff, I thought I'd leave some breadcrumbs here for future seekers.