Link to home
Start Free TrialLog in
Avatar of TacoFlavoredKisses

asked on

Mail coming from a host in our network

We have been getting listed on a blacklist because mail is coming from several EHLO names in our network on the same IP.  We have several mail servers, so this is expected.

We are seeing however two listings from the domain that we are unsure of.  Doing some research it looks to be related to McAfee products, but we are not using any on our mail systems.

Any ideas what this may be?

Also, any issues with having several mail servers all sending out the same IP with different EHLO names?
Avatar of jhill777

Who is your ISP?
Avatar of TacoFlavoredKisses


It is a Time Warner pipe
Avatar of Felix Grushevsky
there are servers that check that EHLO names is resolving to the IP where the mail is coming from.  So make sure that you have "A" record for each EHLO name and "A" is pointed to the sending IP

Any other thoughts on the
I imagine your problem is a bunch of companies are using that anti-spam method of requiring that the reverse PTR records match the name of the mail server sending the mail so using multiple mail servers with different ehlo names is causing the problem.  No shit, right?
I think you need to add an MX record for each mail server to resolve to the correct record on file with your ISP.  For example, if your ISP has your PTR in DNS as xx.xx.x.x, that sending IP and FQDN has to match.  Creating an MX record in your DNS for each server, i.e Servername - Mx record - should fix it, I think.  My head hurts thinking about it and only a couple big companies use this because it's a headache when nobody has their reverse PTR set up correctly, even though they should, and your users all come crying to you that some guy has been sending them important emails but they never get them because your mail server is dropping the connection instantly when the reverse PTR doesn't match and not notifying anybody that the guy is trying to send email.  There are usually no bounceback messages or anything.  My configuration above might need to be tinkered with because I don't know what kind of problems if any, will come up with mulitple MX records pointing to different servers.  If all clients are able to send via any of the SMTP servers then that shouldn't be a problem but I'm not sure about receiving if you have their Outlook profiles configured to pull mail down from which would be your ExchangeserverA and but DNS is resolving exchangeserverA, B, and C all to  
Clear as mud?
Or maybe it would have to be A records and MX records, now that I think about it.  So you would have multiple servers all with the same A record of as well as internal MX records....I think  I'm confusing myself even.  Sooo...your DNS might have to look like this if it will let you?  Basically, when the mail comes out of your domain, all the email has to match your Reverse PTR so you have to get all your servers to look like no matter which one sends it, all the mail is coming

Name                                             Type                                        Data
exchangeserverA                        MX                              
exchangeserverA                          MX                             
exchangeserverB                           MX                             
exchangeserverB                            MX                           
exchangeserverC                           MX                            
exchangeserverC                            MX                             
mail                                                  Host (A)                               192.168.x.x (Ip of exchangeserverA )
mail                                                   Host (A)                              192.168.x.x (ip of exchangeserverB)
mail                                                  Host (A)                               192.168.x.x (ip of exchangeserverC)
mail                                                   MX                               
That would cause mail to try and flow into the wrong places with the MX record that way.

Our MX record goes to a cluster of Barracudas, and is not evewn the same IP as the one mail gets sent from.  Most filters/mail servers just care that your mail comes from an IP that HAS a reverse DNS entry.  Half the ones I see people sending with are not at all the same as their EHLO.

I think the easier solution may be to change the PAT to send as a different IP for each mail server, and set up reverse DNS for each of them.

It is odd because it has not been an issue in 4 years of sending multiple mail server platforms out the same public.  I think as spammers get craftier the people reporting and black listing are getting more strict.
Avatar of jhill777

Link to home
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
Start Free Trial
Still wondering what causes the MX logic ones if anyone else has any insight
Not sure if I understand your question correctly. Your outgoing emails are blacklisted because you have several EHLO names due to different mail servers that send all mails out through a single IP, correct?

Could the MXLogic thing be related to using MXLogic outbound filtering which would require a smarthost configured on the mailserver that points to the MXLogic outbound filtering service?