A reverse DNS resolution is most commonly used for these four purposes:
- Originally: As a network troubleshooting aid, such as traceroute, ping, receipt confirmation trace header for SMTP email, forum tracking, and similar cases.
- Email Anti-Spam techniques: Allows for the domain names in the rDNS to see if they are from dialup users, dynamic IPs, cheap Internet Services, and similar. Some corporate anti-spam services take the view that the vast majority (not all) of e-mail originates from a computer can be spam, and the spam filters refuse e-mail with certain rDNS names. Nonetheles, most spam is usually originated from unptched servers within corporate networks, which may make rDNS seem less useful.
- A Forward-Confirmed Reverse DNS (FCrDNS) verification: This can create a form of authentcation showing a valid relationship between the owner of a domain name and the owner of the server that has been given an IP address. While not very thorough, this validation s strong enough to often be used for whitelisting a domain to the server. This is usually the case to prevent spammers and phishers from passing server verification with their zombie computers, to forge your domain name.
- System Logging and Monitoring Tools: OFten used by system admins to receive entries with the relevant devices specified only by the IP address(es). This gives more human-friendly data to write the log using the domain name rather than the IP address when doing a reverse lookup to perform these tasks.
PTR stands for Point Record.
It is a "Pointer" to a canonical name. Unlike a CNAME, DNS processing stops and just the name is returned. The most common use is for implementing a reverse DNS lookup, but other uses include such things as DNS-SD (DNS-based Service Discovery).
How to enable rDNS for my VPS/Dedicated Server?
To prevent misuse of this service, you will have to contact us with your request and necessary information to get this feature enabled. You cannot set it up yourself, although it is a feature we are considering for the future.
How long does it take to have rDNS configured for my server?
Because of the nature of this type of configuration, it can take between 12 and 72 hours from the moment we received your request. This often includes the time it takes for DNS information to be properly propagated to all DNS servers that handle it.
Can Un-managed Dedicated Servers receive this benefit?
With un-managed, tipically most requests you send to us will not be resolved, because of the nature of this service. However, we will assist you with "container related support", which entitles server restart, rebuild, etc. And because an rDNS is not something you can do on your end, this is also considered part of a "container related support" issue. Please note that installation and removal of third party apps for un-managed servers will not be taken into consideration.
What information should I provide to you?
Your Dedicated Server's IP Address (if multiple IPs, the one you want for the rDNS to point to, usually the primary)
The IP and Domain of the domains you wish to link with the rDNS resolution.
A please and a thank you.
Please note that if the information provided is wrong, it could cause delays and complications for your server, as well as the linked domain or IP addresses. So do be careful with this.
If you still have questions or need further assistance, feel free to contact us using our support ticket system.
