Hi,
(did not read the whole thread here, so sorry for might saying things already said before)
Backup MX is a good thing and a good service to offer for business customers (even there are many different definitions of business customer in the ISP world :)) with their own mail server. Problem, as stated before, is that it's hard for you to do full validation against spam, virus and most important "recipient" validation. the worst thing you can do is accepting all mail for a domain.
the problem is, every customer has another type of mail server (even if there are a lot of ms exchange servers of course). so you would need a way to propagate user database from the customer server to your server in a reliable way.
an easy way around this is offering an mx proxy service instead of the mx backup. that means customer domain mx goes to your server, your server does "recipient validation" with caching. that means on each incoming mail your server will ask the customers server (in a standard smtp dialogue) if the recipient exists and only then accepts the mail on your server. this checking results are cached and that way your server can also accept mails in the case where the customers server is off-line for a while.
but as also said here before: to offer such a service you really need what you're doing, there is nothing worse than a bad configured mail server in the internet :) so if you have the possibility work with a partner which knows the technology well.
greets Marco
On Thu, May 24, 2012 at 6:57 PM, Viktor Steinmann stony@stony.com wrote:
Heya Benoit
Here's the view from a Business customer, who used to work for ISPs:
- Why would business customers _need_ their ISP to operate a backup MX for
them?
- If the customer is multihomed, there's almost no need for this. One
exception: Customer wants to catch possible misconfiguration of DNS and/or mailserver on his side.
- For a non-multihomed customer, mail or Internet in general should not be
*that* business critical. If the customer doesn't want to be multihomed, but still sees mail as a business critical application, I would recommend to outsource mail serivces completely (newspeak: cloud).
- Is it true, that most ISP offer this kind of service?
If there's a paying customer, there's a services who will provide the service. I remember that in the "old" days of the internet, we would implement almost every hack for customers. Nowadays, that marketing people, project managers and process designers are running ISPs, it's most probably not that common anymore...
Kind regards, Viktor
swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog