1

I will try to explain the context.

2 VPS with PLESK 11.5

The first (named vps67877.ovh.net - we call it v67) is a mail server (ip 37.187.33.38) The second (named vps68789.ovh.net - we call it v68) is an hosting server. (ip 92.222.8.114)

When I have a customer, I create the hosting part in v68. I create all the email adresses on v67.

For illustrate, we will take a domain we have : itbag.fr. Here is the DNS entries :

92.222.8.114 / 24   PTR itbag.fr.
blog.itbag.fr.  A   92.222.8.114
ftp.itbag.fr.   CNAME   itbag.fr.
imap.itbag.fr.  A   37.187.33.38
itbag.fr.   NS  sdns2.ovh.net.
itbag.fr.   NS  vps68789.ovh.net.
itbag.fr.   A   92.222.8.114
itbag.fr.   MX (10) mail.itbag.fr.
itbag.fr.   TXT v=spf1 +a +mx -all
mail.itbag.fr.  A   37.187.33.38
ns.itbag.fr.    A   92.222.8.114
pop.itbag.fr.   A   37.187.33.38
pop3.itbag.fr.  A   37.187.33.38
smtp.itbag.fr.  A   37.187.33.38
static.itbag.fr.    A   92.222.8.114
static2.itbag.fr.   A   92.222.8.114
static3.itbag.fr.   A   92.222.8.114
webmail.itbag.fr.   A   37.187.33.38
www.itbag.fr.   CNAME   itbag.fr.

I have several domains like that.

In my v67, I don't activate the DNS zone. I just say who are the servername :

114.ip-92-222-8.eu. (<= reverse DNS of v68)
sdns2.ovh.net. (<= By my provider)

Services works perfectily. But this week end, we have a spam attack... I don't know how and why, but we've got blacklisted by many DNSBL. I succeed on deleting all spams on v67, I succeed to contact all DNSBL for delist us...

When I check my configuration on MXTOOLBOX here is the report :

SMTP Reverse DNS Mismatch   Warning - Reverse DNS does not match SMTP Banner     
SMTP Reverse Banner Check   OK - 92.222.8.114 resolves to 114.ip-92-222-8.eu

SMTP TLS    OK - Supports TLS.  
SMTP Connection Time    1.264 seconds - Good on Connection time     
SMTP Open Relay     OK - Not an open relay.     
SMTP Transaction Time   3.635 seconds - Good on Transaction Time

During my communications with some DNSBL, I get a tips for one of them :

Please could you update the rDNS on this IP to be something more specific to the sender and/or your organisation rather than the generic pattern that the provider has assigned by default. You may need to contact your provider in order to accomplish this rDNS change. Continuing to send mail from an IP with a generic rDNS pattern is likely to affect your Cloudmark reputation score in the future as well as your reputation with many ISPs and DNSbls.

For instance mail.example.com would be considered far less generic than 208-83-136-1.sfo.example.com or hosted-by.example.com

But... I don't understand what they want me to do. Do I have to add a specific DNS entry like I don't know...

37.187.33.38.itbag.fr A mail.itbag.fr 

I'm totaly lost...

1 Answer 1

3

Let me skip your somewhat wild zone information and lead you to the the main problem as I see it:

Your Mailserver is

mail.itbag.fr

which resolves to

37.187.33.38

which has a reverse mapping to

38.ip-37-187-33.eu

This is not good in terms ob SBL/Antispam rules.

Further your mailserver greets:

# telnet 37.187.33.38 25
Trying 37.187.33.38...
Connected to 37.187.33.38.
Escape character is '^]'.
220 vps67877.ovh.net ESMTP Postfix

which is yet another hostname. Same is true for v68.

I would suggest bringing those names in line first and see if that helps the situation.

2
  • Hi, thank you for your answer. My problem is, there is a lot of others domains on this server. mail.itbag.fr is the same as mail.la-ligne-web.com or mail.distridog.pro And this is the problem, i don't understand how to have the same name in order to be clean.
    – PandaJedi
    Jun 12, 2014 at 9:38
  • Try setting vps67877.ovh.net as PTR for 37.187.33.38. Do for v68 same with 92.222.8.114.
    – tim
    Jun 12, 2014 at 12:32

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