On Thu, Jan 03, 2008, Ugo Bellavance wrote:
>I will probably have to design an e-mail (and other components)
>infrastructure for a small ISP soon (WISP).
See my previous post on sizing mail servers. The setup there is
in use at several of our regional ISP customers, and has been
very solid. It's a design that has evolved since we started
building and selling systems for ISPs in 1994.
>I'm doing some research to determine which components would be best to
>offer e-mail services to their client and allow the staff to manage
There are various tools available to do this. I have set up very
restricted webmin configurations so the support people at the ISP
could do the necessary things easily with minimal chance of major
screwups (after I've patched some things in webmmin that allowed
it to remove /home when somebody typed in a bad directory :-).
>I usually use virtual machines a lot for isolation and easy backups and
>migration (when a hardware node is underpowered, it is easy to migrate one
>or more virtual machines to another hardware node easily).
>I have looked at iSCSI and drbd for high-availability of the storage:
>This looks like it should be doing a great job of high availability
>For mail server, I guess I should look at an MTA and IMAP/POP server that
>supports LDAP and/or MySQL for users. Postfix should be a good choice for
>MTA, as I know it (at least a little, but I know sendmail better). For
>IMAP/POP, I'm not sure... Would dovecot be sufficient, or should I try
>cyrus. I'd rather use components that are available for base or extras
>repository (or rpmforge). I think that squirrelmail and horde would do a
>good job for webmail.
The systems we build have postfix/amavise/clamav, courier-imap,
and usually horde/imp for webmail. I personally don't like Cyrus
as I prefer to use standard Maildir which allows easy clustering
for mail delivery and IMAP/POP access.
>There shoudn't be any troubles having some redundancy for DNS, web servers,
>mtas, but what about IMAP/POP? linux-HA? MySQL replication should be
>enough, I guess. Or maybe linux-HA as well. I wonder if I should add GFS
>to the mix to have multiple IMAP/POP servers use the same storage. Or
>maybe IMAP proxies?
> Any insights welcome
I hope you're not charging your client for your learning curve.
INTERNET: email@example.com Bill Campbell; Celestial Software LLC
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