Solved

reverse DNS lookup

Posted on 2012-04-03
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Last Modified: 2012-04-03
SO i have this challange that AOL keeps bouncing back emails sent from my Exchange 2010 server hosted on 2008r2.
We use the Default Sent Connector (Use Domain Name System MX record to route mail automatically")
This works fine on so far alll email sent out.... BUT AOL... they seem to do a Rerverse DNS lookup and that is not good as we do not have them set correctly (the have different names (our hosts has his own naming is on there)
Yet the host is willing to change the naming to what ever i need...
So here is my question ...
What do i tell him to name it... so email wont get bounced back.
my FQDN is for example SERVER.Domain.com and it is on a public IP 1.234.567.89
i did setup up reverse DNS on the servers DNS settings for the IP but i am not sure what to tell the host to name it too so it will work...
 
Thanks for your help...
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Comment
Question by:Andreas-NYC
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20 Comments
 
LVL 21

Expert Comment

by:Papertrip
ID: 37801339
Your sending servers PTR and A records need to match.  If your outgoing server is named SERVER.Domain.com then make sure there is an A record for that which points to 1.234.567.89, and a PTR record for that IP which points to SERVER.Domain.com

You can put your IP into http://network-tools.com/ to verify what the PTR record resolves to.
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LVL 2

Assisted Solution

by:Anthropomorphic_Personification
Anthropomorphic_Personification earned 333 total points
ID: 37801366
People can have all sorts of rules to deny email based on the helo/ehlo domain, fqdn, reverse look up etc.  Also some email that is getting through may be getting marked down by antispam systems.

All you need to do is:

1) make sure the fqdn name for your smtp server maps to the connecting ip, i.e. server.domain.com maps to 1.234.567.89

2) make sure that reverse dns maps back to the fqdn, i.e. 1.234.567.89 maps to server.domain.com

3) make sure the helo/ehlo line sent out by your smtp server is your fqdn (server.domain.com).

This should eliminate most problems with antispam systems.
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Author Comment

by:Andreas-NYC
ID: 37801370
I dont think i have a PTR record set i have A records set
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LVL 21

Expert Comment

by:Papertrip
ID: 37801380
Unless your ISP has delegated reverse authority to you or your hosting provider, then it is they who you will need to contact to get your PTR record updated as they own the IP and are authoritative for it.
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Author Comment

by:Andreas-NYC
ID: 37801445
So they will change the CoLocation Bandwith Provider sets the Reverse DNS to my FQDN and make a correct pointer to the IP ? not done on my servers DNS ?
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LVL 2
ID: 37801465
Yes your provider will have to set the reverse DNS on their systems as they would be the netblock owner.
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Author Comment

by:Andreas-NYC
ID: 37801556
yes they will set it .. but do i have to tell them what to set it to based on my FQDN ? or will this go by IP address only ?
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LVL 21

Expert Comment

by:Papertrip
ID: 37801572
You tell them the FQDN of your outgoing name server and which IP you want changed, they will know what to do.
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Author Comment

by:Andreas-NYC
ID: 37801595
I have 4 IP's available on MY network... do ihave to give them all 4 or just pick one and make sure an A record is available for FQDN SERVER.Domain.com  i think i have 4 A records each pointing at the FQDN on each IP...
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LVL 21

Expert Comment

by:Papertrip
ID: 37801628
All you need to worry about right now is the IP that your sending server is using.  Make sure the A record for your sending server is pointing to that IP.
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Author Comment

by:Andreas-NYC
ID: 37801662
I have a MX record that is pointing at mail1.Domain.com  isnt that what Exchange will use when it sends out email ... so i have to give them that  or really only the FQDN  Server.Domain.com
Sorry for the hassle i just  have to make sure i am doing the right thing...
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LVL 21

Assisted Solution

by:Papertrip
Papertrip earned 167 total points
ID: 37801684
Your MX record is not involved here.  Whatever you configured your Exchange server to announce itself as in the SMTP banner / HELO response.  If your server is configured to be Server.Domain.com then that is what you give them.
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Author Comment

by:Andreas-NYC
ID: 37801695
thank you so much... i will go right on it...

Thanks to everyone who helped me towards this issue...
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LVL 2

Accepted Solution

by:
Anthropomorphic_Personification earned 333 total points
ID: 37801729
MX record is used by other smtp server to route mail to you.

What your need to do is find out what ip address your mail server is connecting from:  

Connect to your exchange server. open a browser and goto www.google.com, type "what's my ip" and the first line in the results will be the IP address that google is seeing.

Give this IP to your provider and ask them to set up a PTR record using this IP and the fqdn of your mail server (i.e. mail1.domain.com if that is what you are using).

Also make sure your fqdn name is set to the connection ip given by google above.
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Author Comment

by:Andreas-NYC
ID: 37801776
thank you .. i passed the FQDN and the IP to the Network Provider... and hope this will fix the Reverse DNS issue... thank you very much...
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Author Closing Comment

by:Andreas-NYC
ID: 37803444
Good work and thanks for the expert advice.. all works like a Charm...
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LVL 21

Expert Comment

by:Papertrip
ID: 37803549
Glad you got it working however I'm not sure why the other expert got the accepted solution and an additional assist, all of that info was provided first by me in both occasions.
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Author Comment

by:Andreas-NYC
ID: 37803562
ops i made a mistake sorry ... i hope i can fix that somehow...
0
 
LVL 21

Expert Comment

by:Papertrip
ID: 37803565
It's ok just remember that us Experts work for points, so please assign them properly when possible :)
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Author Comment

by:Andreas-NYC
ID: 37803574
yes i will ... maybe i can fix it somehow....  you deserve it ... i am so sorry ...
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