Re: [exim] Gmail's new 'suspicious sender' flag

On 11/07/11 20:11, Emmanuel Noobadmin wrote:
> On 7/11/11, Ian Eiloart <iane@???> wrote:
>> Ooh, the legitimacy of a mail server on a dynamic IP is pretty low already.
>> When it's compromised, I don't think it has much legitimacy left!
>
> I wasn't thinking so much of mail servers on dynamic IP but spam sent
> through valid mail servers such as an ISP from a compromised client,
> or a spammer using the same ISP sending spam on a dynamic connection.
>
> This comes from experiences where my clients' intended recipient
> running Barracuda rejects emails because the dynamic ADSL IP in
> question (specifically pointed out in the bounce) was apparently
> detected to be spamming some time ago.

That's deep header inspection then - you shouldn't normally reject mail
because the 2nd or 3rd level of received headers is listed in a DNS
block list. That is a common mis-configuration of Barracuda appliances.
It means that innocent users of an ISP that has been good and listed all
their non-mail blocks in the Spamhaus PBL (for example) are falsely
rejected.

Many a bad word has been uttered around the world upon discovering email
being rejected by one of those systems.