Mailing List Message #100903
From: Lyle Giese <>
Subject: Re: REPOST: How to setup up a secondary mail server?
Date: Tue, 19 Oct 2010 14:29:05 -0500
To: CommuniGate Pro Discussions <>
Jeff Wark wrote:
>  On 10/19/2010 2:16 PM, Lyle Giese wrote:
>> Kirnauskis Postmaster wrote:
>>> On 19.10.2010, at 20:51, Jeff Wark wrote:
>>>>>> 3. Have knowledge of all the addresses in all handled domains
>>>>> How can this be achieved?
>>>> I'm just chiming in, but I believe with a standard CommuniGate [no
>>>> LDAP directories or anything, all accounts are local], you would
>>>> need a helper of sorts.  This helper would scan each email and
>>>> verify that the accounts are valid.
>>> Jeff, thanks for participating! :)
>>> If you were right, that would mean it was quite complicated (read:
>>> out of hands of a fairly educated mail administrator) to setup a
>>> well-functioning backup mail server with CGP. I would be very
>>> disappointed if this was the case. Multiple mail servers should be
>>> pretty "normal stuff", don't you think?
>>> --
>>> Kirnauskis Postmaster
>> It's a shame that CGPro does not implement some type of SMTP
>> verification before accepting email for routing to a foreign.  Many
>> other mail servers and email filtering appliances use SMTP to verify
>> an address exists before accepting and relaying an email.
> Reverse connect is a feature of CGPro, but it is normally considered a
> form of abuse.
> _snip_
> Reverse Connect
> This option tells the SMTP module to verify non-local Return-Path
> addresses by connecting to the mail servers hosting those addresses
> and verifying that those servers accept the specified addresses.
> If this option is set to Add Header, the addresses that cannot be
> verified are not rejected. Instead, the X-Reverse-Check header field
> containing the verification failure code is added to the message.
> Note: Reverse Connect processing is not used for incoming SMTP
> connections from Client or White Hole network addresses.
> Note: If the Verify Return-Path option is set to Nobody, this option
> is not used.
> _snip_
> I assume the same would be felt of email addresses destined for a
> foreign domain...unless it was your own server you were testing
> against.  I'm babbling.
>> But then that would have been a needed feature if they would have
>> stayed in the ISP marketplace, but Stalker abandoned that market when
>> they stopped selling CGPro without the Outlook MAPI connector.
>> Lyle Giese
>> LCR Computer Services, Inc.
Reverse connect is not what I am talking about.  Reverse Connect
attempts to verify the SENDER's email address.

When relaying, we want to verify that the receiptent's address exists
before accepting email on the behalf of that domain.  However the
receiptent's email server would need to accept those verify attempts as
legit and not block them.

Barracuda does that with their mail filter and several mail server
packages have that as an option when setting up relay service.

Lyle Giese
LCR Computer Services, Inc.

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