Resolved Is rDNS possible for multiple domains sharing a single IP?

[Yaniv Zahavi]

Server operating system version

CentOS Linux 7.9.2009 (Core)

Plesk version and microupdate number

Plesk Obsidian v18.0.43_build1800220414.18 os_CentOS 7

Hi,
I read through a few similar this post title so sorry if this may seem a little redundant but none gave me the answer I was looking for

Basically I just need to know if there is anyway to setup rDNS on different domains that are sharing the same IP address. From my general understanding only one IP can be associated as an rDNS to a single domain and so this is not possible.

I wanted to know if there is a way around that or if its really about getting additional IPs on the server for each domain. The problem is that the host providers will not provide IPs for that reason alone so I'm not sure how to handle that.

Thanks in advance.

 

[WebHostingAce]

In this case, You can setup the rDNS for the Host Name

 

[Yaniv Zahavi]

rDNS is setup for the Host Name. If I understand you correctly and what you referring to, if from command line I run: dig -x xx.xx.xx.xx , it resolves back to the server Host Name correctly.

The problem I'm running in to is that the emails are going to different email providers, mainly Gmail, as spam. Once I assign a dedicated IP to one of the domains and built a PTR record for it using the dedicated IP that was assigned to it, then the emails are getting delivered fine from that domain right into the Gmail inbox.

The host provider will not provide a dedicated IP for each domain hosted on the server which I completely understand. I'm trying to figure out how a rDNS can be assigned to a domain name that is sharing the IP with other domains.

Has to be a way, how do email providers like Gmail, Hotmail... get around that and able to resolve the rDNS properly? I'm not sure if I need to make changes in plesk, the server, the domain dns zone or something else.

 

[WebHostingAce]

Tools & Settings > Server-Wide Mail Settings > Outgoing mail mode > Send from the specified IP addresses

 

[Yaniv Zahavi]

Did not work :-(

I changed the settings from Send from domain IP addresses and use domain names in SMTP greeting to Send from domain IP addresses, tested and emails where still going to spam. As soon as I assign the dedicated IP back to the domain the emails go straight to Gmail inbox.

 

[WebHostingAce]

Did you change to "Send from the specified IP addresses"? Then select your server IP?

If you did, You should have "Received: from server.hostname.tld" with your server IP in the email header now.

This should have solved the rDNS issue

 

[Yaniv Zahavi]

My mistake I picked the wrong option.

I didn't want to post back so fast without doing more tests but I think this may have worked

I'll be doing more tests throughout the next cople of days so if anything changes in my observation I'll post back, if no additional post then that settings update worked!

Thx for all your help.

 

[mow]

Tools & Settings > Server-Wide Mail Settings > Outgoing mail mode > Send from the specified IP addresses

Isn't that only for cases where the server has more than one IP? There isn't much to select otherwise ...

@Yaniv Zahavi What you should end up with is, you have one fully qualified domain name you will send all mail from, set the IP's rDNS to match that FQDN, and then set the SPF records for the other domains so that your mail FQDN is listed as allowed in all of them.

 

[lessram]

@mow Sorry for the question.. But how to tell plesk to send all mails from one FQDN ? THx

 

[lessram]

No one can help?

 

[pralhad]

No one can help?

For anyone who are here to solve this issue, you should add rDNS to your server IP with your server's Full Hostname which you are using in Tools & Settings > Server Settings.

Then go to Tools & Settings > Mail Server Settings an search for Outgoing mail mode option.
Choose Send from the specified IP addresses with your desired IP where you have added your rDNS.

This should solve your issue.