We host our own mail server (SBS 2003). We have a T1 connection to the Internet, with a dial-up connection for backup. The fail-over to the modem works great for emergency Internet access; however, since our DNS is hosted with the T1 provider email does not function while on the backup connection. Any suggestions as to the best way to provide email connectivity for our users during a fail-over?
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Unfortunately there is no cable or DSL offered in our area (we are pretty remote). We can live with the slow speed. For one we are not that large a company -- at least as far as number of email users goes; and two, it's the only backup option we have :-)
I can get a static IP for our dial-up for an extra $5/month.
Understand. Well, if you can get a static ip, then you would need to have an MX record in place with your DNS provider to point to the ip of the dial-up in order to receive email. (You're not receiving mail now during your fail-over, because all your mail is still being routed to the IP of your T-1)
To send mail, you can create an SMTP Connector in Exchange that would forward outgoing mail to your dial-up ISP. You just need to identify a host name or IP Address to your ISP in the "Smart Host" area on the SMTP Connector and the mail will be forwarded to them for delivery.
For inbound email, if the provider allows inbound port 25 traffic then a dynamic DNS host account is ideal.
I have talked about this here:
http://blog.sembee.co.uk/a
Basically you have the dynamic DNS host pointing to your regular IP address, then in the event of a failure you switch to the dial up account and change the dynamic DNS host.
Outbound email can be a little trickier. If you don't mind manual work then create an SMTP connector on demand. If you are looking for automatic, this can be a problem, unless you are going to use the same service provider for both services.
Simon.
The solution must be automatic. I ordered a static IP for our dial-up account. For incoming email I'm going to add an MX record with a lower priority to our DNS that points to the dial-up IP. For outbound I will create a "Smart Host" SMTP connector on the Exchange server pointing to the SMTP server of the dial-up ISP.
Please correct me if I'm missing something.
The problem is going to be outbound email.
There is no failover capability with Exchange for outbound email. It is either load balanced or nothing. Therefore if you enter the Smart host of the dial up provider and they reject the email because it is not coming from their network, the user will get an NDR. The only way to have email going out through two different providers without causing a problem is to have a third host involved that is provider neutral - I use my web server which is in a data centre. It doesn't matter how the email gets to the server.
Simon.
Have you considered a 3rd party solution like http://www.exchangedefende
-Should your server be offline they hold all mail until you are back on line (for up to 7 days) and then forward it to your server
-E-mail is routed through them allowing you the protection of a "smarthost"
-They provide Virus and spam filtering with desktop and/or web monitoring/management capability
-they provide 1 year archiving of all e-mail for 1 year
-while your server is off line you can access unreceived e-mail through a web interface
-Cost is $2-3/mailbox/month
Others offer similar services, but it is my preference. There are more basic backup MX services like www.no-ip.com which only offer the mail back up for 7 days, but they are only $30/year/domain
Thanks for the suggestions. I have looked at some third party solutions (such as MXSave) which look pretty good and seem very affordable. The problem is that I have Blackberry users that don't want to have to go to a website to access their email. I know, I know, it sounds rather petty, but some of them are the owners of the company -- nuff said!
Anyway, I think a spin-off of Mestha's suggestion will work for me. A dynamic DNS entry that points to the primary server under normal conditions and then can be changed to an alternate mail server within minutes of an outage. This way I can point to a mail server under my control and setup the mailboxes of BB users to forward their email to the BB devices, as well as, allow other types of access to the non-BB users.
One thing I did particularly like about MXSave is that it automatically forwards any mail it receives back to your primary mail server once it's back up. Just makes "cleanup" after an outage automatic. Thought it was a great feature though.
Any further thoughts, suggestions, etc.?
>>"One thing I did particularly like about MXSave is that it automatically forwards any mail it receives back to your primary mail server once it's back up."
Exchange Defender does this as well. Basically it is a backup and preliminary line of defense for your own Exchange Server, not a replacement.
Good luck with it slattdog.
Thanks,
--Rob
Business Accounts
Answer for Membership
by: MrLonandBPosted on 2009-10-22 at 07:45:35ID: 25634822
I wouldn't use a dial-up connection for email -- I might suggest spending a few extra bucks a month for a DSL line if having a backup connection is critical. Because not only the speed of processing mail comes into play, but I am not sure whether you have a static ip with your dial-up that you would need to point your MX records to -- to receive incoming mail.
You can get a DSL connection with static ip addresses for around $60.00 a month (not top-end though) that would get you by during a T-1 failure.