Re: [exim] Greylisting - how do you implement?

Peter Bowyer wrote:
> On 08/07/07, Renaud Allard <renaud@???> wrote:
>>
>> Martin A. Brooks wrote:
>>> Marc Perkel wrote:
>>>> I have a reall simple way to do it. And I'm using it on several hundred
>>>> domains and it works. Suppose you have 1 MX record. Add 2 more dummies.
>>>>
>>>> dummy1.example.com 10
>>>> real.example.com 20
>>>> dummy2.example.com 30
>>>>
>>>> Gets rid of almost all your bot spam and is far faster and easier than
>>>> greylisting.
>>> Derrick asks about greylisting. You, effectively, give him advice about
>>> making strawberry cheese cake
>> I don't totally agree. The solution Mark Perkel explained is about the
>> same in effect as greylisting but is much more simple to implement.
>> The drawbacks of his solution are:
>> -you cannot whitelist
>> -you cannot control the minimum retry time
>> -you must have more than one IP
>> The good point is:
>> -extremely simple to implement
>> -very lightweight
>
> My big worry about this is that you're completely dependent on the
> behaviour of the other MTA - you've no logging, nothing to tweak,
> can't whitelist, just have to trust that the people sending you wanted
> mail are going to do the 'right thing'. That alone has kept me from
> trying it.
>

Yes, I forgot this drawback: you have no logs of the attempts at all.

However, for the behaviour, any decent MTA should try MXes one by one
until one works.