>>>True. But LAN cards and MAC address change too. I find that more and more of my clients start to restrict or outright ban use of client emailing to SMTP. And I don't see an easy solution. Thank you.
>>
>>How often MAC Address is changed?
>>When you change Computer or LAN card.
>>In these cases you client should do something, right?
>>Buy a new LAN Card or new computer.
>>So in addition to this He/She should add new MAC address to SMTP Security.
>
>I agree with you that it is not a big deal. But this customer - a big corporation - wants to push the buck. That is, they don't want to worry about doing it even if it is only once a year. They would rather have Dmitry deal with it <g>.

I really hates sysadmins!!!