rdns record

reverse Domain name resolution, in contrast to the usual forward domain resolution, provides IP address to the corresponding domain name. IP Reverse resolution is primarily applied to mail servers to block spam, especially in foreign countries.

First, the domain name resolution process1. The browser checks its own cache, and the cache time varies from a few minutes to an hour, determined by setting the TTL property.2. If 1 is not found, check the OS cache, such as the host file under

The problem is due to anti-spam software, which has been confirmed by Sina that they recently deployed a set of anti-spam systems. By default, the mail server sends its own FQDN name when it makes a helo command to establish a session with a Remote

Windows Server 2003 building a mail serverBecause Windows Server 2003 defaults to not installing the POP3 and SMTP services we need to build our mail servers, we need to install them ourselves. Here's how:1. Place the Windows Server 2003 System CD

Due to the spread of spam, various anti-spam technologies have been proposed. Domain Name reverse resolution (rdns) is the most common type. More email servers need to check IP reverse resolution (PTR) records, especially foreign email servers, in

Cui NIDI intruded into the energy management system of the power station using NMAP in US blockbusters and Besides hacking, rocky stealing, and NMAP are good choices for detecting the security of your server.If someone else's host is sniffed and the