Warning - Reverse DNS does not match SMTP Banner

Submitted by gl3ny on Fri, 05/27/2011 - 19:09

back with a new server and 2 ip's

domain1.com xxx.xxx.xxx.xx1 Webserver domain2.com xxx.xxx.xxx.xx2 Webserver, Bulk Email, MailServer

Mx Tools is reporting "Warning - Reverse DNS does not match SMTP Banner" for smtp check for domain2.com

I can get "OK - Reverse DNS matches SMTP Banner" by changing the FQDN to domain2.com but...

http://www.virtualmin.com/documentation/installation/automated#fqdn

...says, "We recommend you choose a name that is not one for which you will be receiving mail" for FQDN.

This seems like a catch 22 for me and don't know which is best. Is it as simple as creating an a record for subdomain@domain2.com and instructing the ISP to resolve to this?

Status: 
Active

Comments

Submitted by andreychek on Fri, 05/27/2011 - 19:23

Howdy -- we generally suggest choosing a name like "host.domain.tld" for your hostname -- and then have your ISP use that same "host.domain.tld" as your reverse DNS.

That should resolve issues such as the one you ran into.

Submitted by gl3ny on Fri, 05/27/2011 - 19:25

ok that's what I thought. Thanks for the speedy confirmation!

Submitted by gl3ny on Fri, 05/27/2011 - 19:52

isp has set rDNS to host.domain2.com for ip

I changed the fqdn to host.domain2.com

Still getting the warning when i do smtp check for the ip. I'm lost now???? lol

Submitted by andreychek on Fri, 05/27/2011 - 20:21

It could take some time for your ISP's DNS changes to propagate.

However, also make sure that you've restarted Postfix, so that it picks up your modified hostname.

Submitted by gl3ny on Sat, 05/28/2011 - 10:23

the rDNS seemed to propagate very quickly. STill getting the SMTP banner waning.

Submitted by andreychek on Sat, 05/28/2011 - 10:53

What is the hostname of your mail server?

Submitted by gl3ny on Sat, 05/28/2011 - 11:02

i have 2 ips

65.111.167.76 (default shared) 65.111.167.77 (added 2 shared)

FQDN v103.mailham.com

v103.mailham.com assigned to 65.111.167.77 mailham.com (mail server) assigned to 65.111.167.77

Submitted by andreychek on Sat, 05/28/2011 - 11:10

Email will go out via the default route that's on your server -- that's typically the first IP address on your server, and usually the one associated with the device "eth0".

I see your mail server banner is setup as "v103.mailham.com" as you had hoped -- however, if your default route uses the IP address 65.111.167.76, and not 65.111.167.77 -- remote servers will see "76-167-111-65.serverpronto.com" as your reverse DNS, since they're actually communicating with the IP "65.111.167.76".

Submitted by gl3ny on Sat, 05/28/2011 - 14:41

The smtp banner issue has been fixed, thank you!

65.111.167.76 (default, eth0) rDNS v103.mailham.com

...but now when I put www.mailham.com in the browser it doesn't take me to the virtual server I created earlier. Instead I have to put in just mailham.com to get there.

Thinking I might have confused the system, I deleted the VS and recreated, with same results.

I have 1 a record in the dns: @ 65.111.167.76

and I created 1 cname: www www.mailham.com

putting www.mailham.com in the browser still doesn't take me there. If I want to use this domaim as bulk mail server should I not be using this IP as a www. webserver now?

Should I create something like list.mailham.com for the mail server?

Submitted by andreychek on Sat, 05/28/2011 - 14:47

It looks like DNS for "mailham.com" is controlled over at GoDaddy. It also looks like there is no result returned when performing a lookup for "www.mailham.com", though I do get a result for "mailham.com".

That means you want want to verify that, over at GoDaddy, that you have a 'www' CNAME setup. If you do -- it may not be active yet.

Submitted by gl3ny on Sat, 05/28/2011 - 15:27

Usually Godaddy DNS is very quick at propagating. I have made changes to DNS since adding the www cname which have propagated.

I think there might be something else going on here?

Submitted by andreychek on Sat, 05/28/2011 - 16:41

Okay, it seems to resolve correctly for me now. They point to the IP "65.111.167.76".

Both "www.mailham.com" and "mailham.com" take me to a page that reads "Test WWW" -- does that sound correct?

Submitted by gl3ny on Sat, 05/28/2011 - 16:49

Yes thats correct, but it doesn't for me so i guess its just time. I guess subdomains propagate very quickly but www with godaddy do not.

I've been swiching back and forth with a www as an "a" record and a "cname" in my case which would be correct or doesn't it really matter?

Submitted by andreychek on Sat, 05/28/2011 - 16:55

Well, the issue may not be with GoDaddy -- it's possible that the DNS server for your ISP cached the 'www' record with the old IP. You may just have to wait until it clear's your ISP's DNS cache.

Submitted by gl3ny on Sat, 05/28/2011 - 19:59

That was it thank you for your patients. I could do with some more patients!