Re: [exim4] mixed up about terminology
On 10/13/2014 8:55 AM, Joe wrote:
> On Mon, 13 Oct 2014 08:19:37 -0400
> Jerry Stuckle <jstuckle@attglobal.net> wrote:
>
>> On 10/13/2014 5:43 AM, Joe wrote:
>>> On Mon, 13 Oct 2014 07:32:40 +0100
>>> Jonathan Dowland <jmtd@debian.org> wrote:
>>>
>>>> On Sun, Oct 12, 2014 at 09:05:14PM -0400, Jerry Stuckle wrote:
>>>>> Among other things, legitimate MTAs have MX records.
>>>>
>>>> Not necessarily. In the absence of an MX record an A record is
>>>> perfectly legitimate.
>>>>
>>>>
>>>
>>> And as I've pointed out to Jerry, a lot of businesses outsource
>>> their incoming email to commercial spam-cleaning services, as well
>>> as larger businesses using separate send and receive servers, and
>>> some businesses receiving email direct but sending via a smarthost.
>>> In each of these cases, the MX would not necessarily have any
>>> connection with the mail sending address. My IP address A-PTR
>>> record pair have no direct connection with any of the email domains
>>> I use, with any MX, or any HELO strings I send.
>>>
>>> There's no one size fitting all with email. Heck, some people use
>>> Yahoo...
>>>
>>
>> Yes, they outsource their anti-spam. But they do NOT outsource the
>> servers themselves.
>
> So people come in every day with a mop and bucket to clean up the email?
>
Nope. All emails (including SPAM) are archived. It is the law for many
companies.
> Google 'anti-spam service'.
>
So?
> Look at GFI Mailessentials Online, to pick a well-known name out of the
> list:
>
> 'Block spam and viruses before they reach your network'
> 'Ensure uninterrupted email even when disaster strikes'
>
> How do they do that if they use the customer's mail server?
>
You need to learn how they work.
>> In many cases, they cannot do so for legal
>> reasons; for instance, in the U.S., many publicly traded companies
>> must keep all emails (even spam) for a specific length of time. The
>> same is true of companies with certain Federal Government contracts.
>>
> Undoubtedly.
>
> 'Archive your important email communications'
>
> How about Mailfoundry?
>
> 'How It Works
>
> MailFoundry Hosted Anti-Spam works by routing your email (MX records)
> to our network data centers where we clean your email and then pass it
> on to your email server. It's really simple and easy to setup, and we
> are available to assist you if needed. '
>
And companies under legal obligations to log all emails can not and do
not use such services. It would make them liable for actions of a third
party, with no recourse against that party.
>
>> And can you identify any legitimate business which has separate email
>> servers?
>
> My ISP, Demon. I'd be willing to bet that Microsoft does, and Google,
> and...
>
No, Microsoft does not (I get mail from them regularly). Same with Google.
Show some proof for your claims - instead of just wild conjecture.
> Anyone whose email load is too great for one server to handle will use
> more than one server. It's a no-brainer to separate incoming and
> outgoing functions, as they require different processing. It's a
> compromise to use one MTA for both. People dealing with lots of
> email, using more than one server, will not connect them all using one
> NAT bottleneck, they will use separate IP addresses, probably in a
> single CIDR block, but not necessarily.
>
Which is easily done via things like load balancing and routing - and
smarthosts. Yet it still keeps the MX record pointing at the proper IP.
>> Just because you do it wrong does not mean the rest of the
>> world does. I can think of a number of companies which will silently
>> drop emails from a configuration such as yours (or at least relegate
>> them to the company's spam folder and not deliver them).
>
> That's OK, I don't do business with them. The pickiest mail hosting
> company I have dealings with is AOL, who accept mail from me with no
> problems. I've been doing this for fifteen years, Jerry.
>
Only 15 years, Joe? I've got over twice that (actually closer to three
times now). I was on Arpanet before there was TCP/IP, back in the 70's.
Jerry
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