Do ISPs have spam-blocking and virus protection?

Do ISPs have spam-blocking and virus protection?

Some ISPs have built-in software that screens out spam, which is the Internet equivalent of junk mail. Some ISPs screen all files for viruses as well. On the face of it, spam-blocking seems like a good deal, but some spam-blocking soft-
ware isn’t sophisticated and merely blocks certain kinds of files, such as
.exe (executable) files or files that are larger than a certain number of
megabytes. You might legitimately receive these kinds of files from co-
workers, in which case spam-blocking is not for you.