[IMail Forum] telnet port 25 security question

[Arriba-R1]

Hello,   I've recently read that one can use "telnet www.thedomainname.com 25" in order to troubleshoot smtp mail problems.   I noticed that doing this with some domains yields a response of the smtp server name and software version.   On other domains such as amazon, or microsoft, there is a failure to connect message.   Is the ability to successfully telnet to port 25 a security issue?    Thanks Kim