Domain issue
Hi,
Server is with specific IP, how to ensure domain is resolving back according to the following? a.b.c.d is the real IP.
smtp.myfavouroteeshop.com <=> a.b.c.d
Server is with specific IP, how to ensure domain is resolving back according to the following? a.b.c.d is the real IP.
smtp.myfavouroteeshop.com <=> a.b.c.d
David Johnson, CD
nslookup smtp.myfavouroteeshop.com
Do you mean you want the FQDN to resolve by DNS to the IP address specified, and the IP address to resolve by RDNS to the domain name specified? The first is easy; the second is not.
ASKER
Do you mean you want the FQDN to resolve by DNS to the IP address specified, and the IP address to resolve by RDNS to the domain name specified?
Yes, can I have details for your way to achieve this?
RDNS can only be set up by your service provider, so you'll need to contact them. There will probably be a charge for this, as the only reason for having RDNS set up is for SMTP FQDN validation during the HELO/EHLO exchange.
Be very, very sure that the RDNS of your MTA is exactly the same as its FQDN, both the DNS lookup and in the HELO/EHLO. Mismatched RDNS causes some receiving MTAs to discard the incoming mail as being from a spoofed domain, and at the very least it causes receiving MTA to look at the email with suspicion.
e.g.:
Your outgoing MTA: EHLO smtp.somewhere.com
Receiving MTA: Connecting IP address is xxx.yyy.zzz.aaa
Receiving MTA: RDNS xxx.yyy.zzz.aaa
RDNS results: www.somewhere.com
Receiving MTA: Hmm ...
Receiving MTA: DNS smtp.somewhere.com
DNS results: xxx.yyy.zzz.aaa
Receiving MTA: smtp.somewhere.com != www.somewhere.com. Add +15 to the spam score for this one
Be very, very sure that the RDNS of your MTA is exactly the same as its FQDN, both the DNS lookup and in the HELO/EHLO. Mismatched RDNS causes some receiving MTAs to discard the incoming mail as being from a spoofed domain, and at the very least it causes receiving MTA to look at the email with suspicion.
e.g.:
Your outgoing MTA: EHLO smtp.somewhere.com
Receiving MTA: Connecting IP address is xxx.yyy.zzz.aaa
Receiving MTA: RDNS xxx.yyy.zzz.aaa
RDNS results: www.somewhere.com
Receiving MTA: Hmm ...
Receiving MTA: DNS smtp.somewhere.com
DNS results: xxx.yyy.zzz.aaa
Receiving MTA: smtp.somewhere.com != www.somewhere.com. Add +15 to the spam score for this one
Better to test + know, than guess.
https://www.experts-exchange.com/questions/29194498/how-to-configure-smtp-in-wamp-server.html provides how to use the Port25 verifier (near end of comments).
Once you've setup your Reverse Lookup, then test with the Port25 tester.
Note: You cannot set your own Reverse IP DNS record, as you don't actually own any IPs.
You ISP or Hosting provider will provide some facility to set this DNS record.
A few providers provide a dashboard function where you can do this yourself.
Most providers require you open a support ticket to set this correctly.
The Port25 tester will verify your IPrev lookup, SPF, DKIM, DMARC, then run Spamassassin across your message, returning results.
Post your real IP + hostname for testing, if you prefer others test this for you.
https://www.experts-exchange.com/questions/29194498/how-to-configure-smtp-in-wamp-server.html provides how to use the Port25 verifier (near end of comments).
Once you've setup your Reverse Lookup, then test with the Port25 tester.
Note: You cannot set your own Reverse IP DNS record, as you don't actually own any IPs.
You ISP or Hosting provider will provide some facility to set this DNS record.
A few providers provide a dashboard function where you can do this yourself.
Most providers require you open a support ticket to set this correctly.
The Port25 tester will verify your IPrev lookup, SPF, DKIM, DMARC, then run Spamassassin across your message, returning results.
Post your real IP + hostname for testing, if you prefer others test this for you.
Dr. Klahn and David, provided explanations and info.
Often service providers will setup the required matching FQDN/rdns
The hard part as Dr. KLahn pointed out is whether the provider from whom you are getting your connection, or where you have your server setup makes the option available to you to request that the IP reflect the pointer name SMTP.myfavouriteeshop.com
To complete the matching forward/reverse lookup references.
Often service providers will setup the required matching FQDN/rdns
The hard part as Dr. KLahn pointed out is whether the provider from whom you are getting your connection, or where you have your server setup makes the option available to you to request that the IP reflect the pointer name SMTP.myfavouriteeshop.com
To complete the matching forward/reverse lookup references.
ASKER
Hi，
Can I have details to set up Reverse Lookup?
Can I have details to set up Reverse Lookup?
Usually, one emails there ISP, service provider where the serverfs hosted and make a request to add a pointer record for IP: a.b.c.s to point to SMTP.myfavouriteeshop.com.
Based on your domain.
1) Forward lookup works (A record returned by DNS).
2) Reverse lookup fails (PTR record missing for your IP).
3) https://www.abusix.ai lists this IP as a suspect IP, so it's highly unlikely you'll have good (or maybe any) delivery/inboxing using this IP.
4) Might be your IP is on an RBL list because it's in Hong Kong + many adjacent IPs are sending SPAM.
5) Likely best for you to use a Mail Relay service like https://MailGun.com in the beginning, then setup an MTA on an IP not on any RBL list.
1) Forward lookup works (A record returned by DNS).
2) Reverse lookup fails (PTR record missing for your IP).
3) https://www.abusix.ai lists this IP as a suspect IP, so it's highly unlikely you'll have good (or maybe any) delivery/inboxing using this IP.
4) Might be your IP is on an RBL list because it's in Hong Kong + many adjacent IPs are sending SPAM.
5) Likely best for you to use a Mail Relay service like https://MailGun.com in the beginning, then setup an MTA on an IP not on any RBL list.
ASKER
Hi,
Must I apply Mail Relay service from https://MailGun.com?
How to set up an MTA on an IP instead?
Must I apply Mail Relay service from https://MailGun.com?
How to set up an MTA on an IP instead?
an MTA is just a name.
The issue with forward.revers having to match is an enforcement, anti-spam type setup on the receiving servers side. You can not control that.
Generally, a reverse that does not exist as in you case is often better than a mismatched record.
You have to check with the administrators of the IPS on whether they provide a way for you to get the change for your IP.
Often, using your ISP as the relay host through whom your server sends all outgoing messages may avoid the individual reverse/forward match requirement.
The issue with forward.revers having to match is an enforcement, anti-spam type setup on the receiving servers side. You can not control that.
Generally, a reverse that does not exist as in you case is often better than a mismatched record.
You have to check with the administrators of the IPS on whether they provide a way for you to get the change for your IP.
Often, using your ISP as the relay host through whom your server sends all outgoing messages may avoid the individual reverse/forward match requirement.
ASKER
Please note MyFavouriteEShop.com is always with a.b.c.d as the IP. My ISP is having no change against it.
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the owner of the i[p address has to set the revrese ip address pointer