I'm not really sure this is the correct place to mention an email issue (related to some of the other "spoofing" postings here), but here goes.
I've experienced a reverse situation. By this, I mean I have had a number of occasions where I've received emails in my Yahoo email account which in the From line, it had my ISP's name and beside my ISP's name, there was a specific email address which had my ISP's name after the "@" symbol. (e.g., sample101@ isp.net). After opening the email, there was a line of some 25 consecutive alphanumeric/special symbol characters shown. (It was not displayed like an underlined link that you can click on and it takes you to some website). [Needless to say, I did NOT click on it for obvious security reasons]. A short message said I had infected folders and needed to remedy the problem. It was "signed" (fraudulently of course) as the "Support Dept" of my ISP.
One odd thing is that the personal email address (shown like the example above) happened to be someone in my own Yahoo address book, though I do not really have any idea how I might know this person (much less have their email contact info in my Yahoo address book).
After expanding the headers and looking at the Received lines, the IP addresses shown all began with the number 10. (e.g. 10.xxx.xxx.xxx). Upon entering the IP addresses into the ARIN WHOIS database, each of these addresses were listed as something referred to as "Blacklist or Blackband" range of IP address numbers (or something similar) in the IANA registry. There was a comment section which said the IP numbers could be used by anyone without any need to do anything/coordinate/register with IANA (or something similar). This seems to me to be some sort of wierd set-up where somehow individuals can get ahold of, and use any of the IP address numbers within the range shown without having to identify themselves, etc. Is there some way to get IANA (or whoever has some regulatory authority out there) to ascertain WHO is using these specific "Blacklist/Blackband" IP address numbers (or whatever it was they were called), and put a stop to this sort of thing?
I did a full scan with McAfee and subsequently, a scan with the Malwarebytes, Anti-Malware program. Neither indicated any problems. I did forward the suspicious email to my own ISP's email spam-reporting center...for whatever good it might do.
Thanks very much for your time and any ideas or suggestions!