On 24/09/10 18:32, kuLa wrote:
On 24/09/10 15:41, Gary Roach wrote:
I got that a valid DNS name isn't present. What do I do about it. Does
this mean that I need to submit something to my ISP or use one of my
existing email accounts for a name or stick in something from the
returns I get from running host. I know what them problem is. I just
don't know how to fix it. I use Verizon Fios with an M1424WR router if
that is any help.
Gary R.
What does it mean is you have to provide name of your mail server into
DNS schema. Basically you have to register your own domain and then
point it into your server, it'll be a good idea if you'll put there an
rDNS record as well as some mail systems are not accepting emails from
system which have no rDNS set up.
I'd suspect that almost no mail servers will accept mail from a sender
without a valid rDNS.
Exim4 when receiving mail has these default requirements for a mail
server sending to it (when it has a local DNS server, and minimaldns has
not been configured true):
- A valid hostname for the public IP address as found from the reverse
DNS lookup, which is the DNS PTR record which your ISP maintains. You
generally cannot alter this directly, but a business ISP should adjust
it to what you want, or at the very least, provide a non-generic PTR for
its own domain. 'Generic' PTRs are those which are basically disguised
IP addresses, issued for dynamic IP addresses, such as
pool-12-34-56-78.isp.net. Any of the many DNS testing websites will show
you your current PTR.
- A DNS A record corresponding to this hostname which points back to the
IP address, which your domain host maintains. You may have a web control
panel for your domain which allows you to make A records.
- A mail server HELO string which is resolvable in public DNS. Just a
domain name will do, and it doesn't have to match the PTR/A record pair.
Exim4 will make up a reasonable HELO, or you can set it explicitly with a
primary_hostname = mail.domain.com (or just domain.com)
directive in the Main Configuration section of exim4.conf.template
(assuming you're using a single configuration file, otherwise it goes in
the conf.d/01_.... file. There must be a public A record corresponding
to this hostname or domain name.
The policies of a mail server depend entirely on the admin staff at any
domain, so there are no definite rules. I use exim4, so I enforce these
three rules, along with a few others. I don't send using a smarthost, so
I can't help with that side of the configuration, but a smarthost which
uses authentication should generally not impose any other restrictions,
as the only authenticated users are its own paying customers. The best
idea here is to ask your smarthost admin staff what requirements they have.
Allegedly, some domains require that your sending domain MX record
matches the PTR and/or HELO, but that's just plain daft. The three
conditions above satisfy AOL, and their mail server policy is quite
picky. The complementary PTR/A requirement will kill nearly all spam and
malware from compromised home PCs, which generally have dynamic IP
addresses and cannot control their DNS records, which is why many
servers demand it.
--
Joe
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