Re: the whole greylisting, spam filtering thing

Hi Leo,



Am 29.09.2017 um 16:57 schrieb Leo Unglaub:
> Hey,
>
> On 09/29/17 15:06, Markus Rosjat wrote:
>> my boss is getting on my nerves that greylisting is basically out of
>> date because of things like outlook.com and mails ending up delayed
>> for ever. So the next logical step would be to deploy a tool like
>> rspamd or spamassasin to examin mail content. These tools need to be
>> trained and if you have a small mailserver with less accounts this
>> could take a while I imagine
>
> i assume that your boss is not an engineer and also not very familiar
> with how emails work. Greylisting it clearly NOT out of date at all.
> Greylisting simply makes use of stuff that is defined in the SMTP RFC.
> Every email server is allowed to temporary deny the delivery of an email
> and ask the sending server for another try.
>

well we use greylisting and I gave MS a free pass but sometimes it
doesn't seem to work anyway but that's ok for me.

> The problem in this case is clearly Microsoft who has no idea how email
> is supposed to work. You have two options here.
>

the customer will always complain no matter how often you explain the
real problem :)

> A: Simply don't care about Microsoft and just send customers to a
> website where you describe the problem and tell them to contact
> Microsoft in order to fix there stuff. This works very well, my Company
> hosts around 2,3 Million mailboxes and we use Greylisting and customers
> are okay with it.
>
> B: You exclude the outlook.com outgoing servers from greylisting.
> Microsoft provides a list of IP addresses that they use for delivery:
> https://mail.live.com/mail/ipspace.aspx
>
>> 65.54.190.0/26
>> 65.54.190.64/26
>> 65.54.190.128/26
>> 65.54.190.192/26
>> 65.55.116.0/26
>> 65.55.111.64/26
>> 65.55.116.64/26
>> 65.55.111.128/26
>> 65.55.34.0/26
>> 65.55.34.64/26
>> 65.55.34.128/26
>> 65.55.34.192/26
>> 65.55.90.0/26
>> 65.55.90.64/26
>> 65.55.90.128/26
>> 65.55.90.192/26
>> 65.54.51.64/26
>> 65.54.61.64/26
>> 207.46.66.0/28
>> 157.55.0.192/26
>> 157.55.1.128/26
>> 157.55.2.0/26
>> 157.55.2.64/26
>
> Greetings
> Leo
>

I also check the spf record files of MS and added them too so we will
see what's going to happen. I need to move to a more up to date setup so
I just check my options what's used these days and yes greylisting works
for me as long as no office 365 is involved but a lot of business
partners of our customers moving to 365 and the email solution so it
becomes a problem for me too. It's just fustrating to see a mail
greylisted from 40 different ips ...

regards

--
Markus Rosjat fon: +49 351 8107223 mail: rosjat@ghweb.de

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