Author: Marc Perkel Date: To: Peter Bowyer CC: Exim, Users Subject: Re: [exim] Paging Marc Perkel: rDNS on junkemailfilter.com checking
host(s)
Peter Bowyer wrote: > On 09/11/06, Marc Perkel <marc@???> wrote:
>
>> Larry Rosenman wrote:
>>
>>> Marc Perkel,
>>> Your junkemailfilter.com server that does the sender verify has what
>>> looks to be dynamic/generic rDNS. This causes
>>> MY server to reject your sender verify:
>>> Nov 8 08:12:24 thebighonker exim[32310]: H=5.ctyme.com (pascal.ctyme.com)
>>> [69.50.231.5]:35579 I=[192.147.25.65]:25
>>> F=<sender-verify@???> rejected RCPT <ler@???>: EL:
>>> () in EL list
>>>
>>> Can you get the rDNS to be more legitimate?
>>>
>>> Thanks,
>>> Larry Rosenman
>>> (Sorry for taking THIS lists bandwidth, but I know Marc is on it, and I
>>> can't email him
>>> Directly because of this).
>>>
>>>
>> Well, the reverse lookup is 5.ctyme.com - I suppose I could change that
>> but why do you think it's dynamic?
>>
>
> Because he has a heuristic for determining dynamic hosts from their
> hostname - like DynaStop does. This is an inherent weakness of such
> schemes, and why you should be cautious in relying on them.
>
> (I've no idea whether this particular pattern would trigger DynaStop,
> but the point is a general one)
>
> Peter
>
>
