I have a few email accounts that are used internally only... via the vacation program and the .forward they pipe the input of the email to a parser to gernerate a html file. These accounts should only receive email from one or a specific list of sending addresses/IPs/etc as if they were to receive spam for example, it would screw up the outputted html. How can I restrict who can send email to a specific address at my site? Basically the equivalent of hosts.allow & hosts.deny but for email and for specific email addresses.

I'm using RH 7.3 with Sendmail. I'd prefer to do this w/o setting up any other software, but am open to options.

i think u can do this via the /etc/mail/access file. refer to the sendmail documentation for this.