Re: [exim] Greylisting - using Exim new features - ratelimit…

>> We use spread/wackamole for failover, and it works really quite
>> nicely, though not perfectly. I'd estimate that downtime is reduced by
>> an order of magnitude.
>>
>
> In my case I have a separate server for people to get their mail from.

You misunderstand me. I'm talking about SMTP services, which I regard as
(a) for incoming email, and (b) for local mail submission. For local mail
submission, high availability means providing high uptime for each IP
address that services the submission, because mail clients won't fall back
to a secondary IP address, even if several are available after DNS
resolution.

> Incoming email goes to the front end spam filters, the spam is removed,
> and the good email is forwarded to other email servers where the users
> get their email.
>
> BTW, Ian, What do you use for a pop/imap server that runs across several
> computers?

We don't provide POP. As a campus service, we think its important to hold
mail on our servers so that we can back it up, and so on.

We use Cyrus IMAP, with four mailstores on SAN storage devices. The SAN
mirroring provides filesystem redundancy here. We're half way through
deploying this, moving from UoW IMAP. The Cyrus IMAP server itself will
eventually be clustered, but we're currently running a single IMAP server.

During the mailbox migration process, we used Perdition IMAP proxy servers
so that we could migrate users without requiring them to change their mail
client settings.



--
Ian Eiloart
IT Services, University of Sussex
x3148