Frequently Asked Questions

1. What is open relay?

   An open relay is an email server that allows any third party connections and the sending of e-mail through it.
   
   Spammers around the world constantly seek out the Internet in the search for a vulnerable mail server and make illegally use of it sending unsolicited emails (SPAM).

2. What is open proxy?

   Like open relays, open proxies can also be used for illegal activities. The difference between them is how the connection happens. While open relays allow someone to establish a connection through Port 25 (SMTP), open proxies allow connections to email servers through a ports range.

3. What is Reverse DNS?

   Reverse DNS is a register that turns a numeric IP address into a host name, this entry is classified in DNS system as a PTR record.

4. What is SPF?

   SPF stands for Sender Policy Framework. It is a technology in which domain owners specify which computers on the Internet can send mail depending on the domain name, allowing the recipient to verify it. For further information, please click http://spf.pobox.com/.