IMail shows the IP of the connecting host in the Log file. The
hostname will also be shown when the remote says helo or ehlo.
Why do a reverse unless it is to determine to accept or reject the
mail? The header already will show the remote hosts name, if one
wishes to see it. I doubt that many users would need more than the
hostname for most filtering purposes. The administrator can see both
in the log (yea, it is a bit of work sometimes) and I think he would
be the one who would have the greatest need to see this kind of data
(so why put in every message?). And Vaughn has a point. If one had
to do the reverse, IMail would also have to hold the processing of
the message while this went on and results were returned, or have to
modify the image in the buffer before creating the file, again
waiting how long before commiting to delivery of the message.
Now I'm not saying it cannot or will not be done in IMail, just
making some comments about how it might work. BTW, I'm not a
programmer so this is a theoretical dicussion. But from all I have
seen about reverse DNS, it is not an effective way to provide a
measure of security. At most it something else to make honest people
do more work to prove they are honest people. If I were dishonest,
I'm sure it is possible to spoof IP addresses and therefore
hostnames, so how would you know where the message REALLY came from?
Daniel Donnelly
Ipswitch Tech Support
__________________________________________________________
| See our Knowledge Base at http://support.ipswitch.com/kb |
In reply to 28 Aug message from [EMAIL PROTECTED]:
>In regards to:
>>(notably sendmail). Very useful at best, and at worst only costs the
time
>for a reverse look-up. Worth adding to the low-priority
>desirable features list.
>I would like to say:
>While I agree that the option to do reverse lookups would be
>very good (as an option), that the time taken for reverse
>lookups can be huge! Huge enough to make the guy at the other
>end think your server timed out, like sendmail often appears to
>do when waiting for reverse lookups to fail... -V
>----- Original Message -----
>From: Aaron Roydhouse <[EMAIL PROTECTED]>
>To: <[EMAIL PROTECTED]>
>Sent: Saturday, August 28, 1999 10:08 AM
>Subject: Re: [IMail Forum] Reverse DNS
>> Doing DNS reverse look-ups and not accepting messages are two
different
>> things.
>>
>> IMail could do a reverse look-up, then if the IP and hostname do not
>match,
>> this could be indicated in the message header to help the eventual
>recipient
>> to identify or filter dodgy email (at their own discretion). IMail
would
>> still accept the mail, whether the reverse look-up matched or not.
>>
>> This is a facility commonly provided by other mail servers (notably
>> sendmail). Very useful at best, and at worst only costs the time for
a
>> reverse look-up. Worth adding to the low-priority desirable features
list.
>>
>> Aaron.
>>
>> ----- Original Message -----
>> From: Daniel Donnelly <[EMAIL PROTECTED]>
>> To: <[EMAIL PROTECTED]>
>> Sent: Saturday, 21 August 1999 02:55
>> Subject: Re: [IMail Forum] Reverse DNS
>>
>>
>> > No, IMail does not, because it is a violation of RFC to not accept
mail
>> from a
>> > host whose IP and hostname do not match.
>> >
>> > Daniel Donnelly
>> > Ipswitch Technical Support
>> > ________________________________________________________
>> > See our Knowledge Base at http://support.ipswitch.com/kb
>> > URL for List Servers:
http://www.ipswitch.com/Support/mailing-lists.html
>> >
>> >
>> > In reply to 19 Aug message from [EMAIL PROTECTED]:
>> >
>> >
>> > >Can someone please tell me whether IMail Server does a reverse DNS
>> > >lookup on receiving messages form another SMTP host ?
>> >
>> > >Do most mail servers in the Internet do reverse DNS lookups upon
>> > >receiving mail ?
>> >
>> > >Thanks
>> >
>> > >Ruediger
>> >
>> >
>> >
>> >
>> > Please visit http://www.ipswitch.com/support/mailing-lists.html
>> > to be removed from this list.
>> >
>>
>> Please visit http://www.ipswitch.com/support/mailing-lists.html
>> to be removed from this list.
>>
>Please visit http://www.ipswitch.com/support/mailing-lists.html
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