I have a SonicWall email filter, which I am very happy with. I accept mail for several domains, which pass through the SonicWall filter and then are forwarded to the mailboxes which are hosted by Intermedia.
Intermedia's Spam filters don't do the job for my clients and me as well as the SonicWall does.
Because my SonicWall is in my office, I am at the mercy of my ISP and Power company. I was fortunate that I only lost Internet service for 16 hours during the Northeast's early snowstorm of October.
My MX records are set up as follows:
5 my SonicWall
10 First Intermedia Server
20 Second Intermedia Server
30 My SonicWall (again)
I put my SonicWall in twice, because SonicWall advised me that many Spammers send email to the lowest priority mail exchanger because they assume that the highest priority has the best anti-spam protection.
So, if my Internet goes out, the email will be delivered to Intermedia, which I have configured with relaxed Anti-Spam settings - I discovered that Intermedia's more sensitive settings produces more false positives than SonicWall.
Spammers are sending email directly to the lower priority Intermedia servers, and my clients are getting too much junk.
I would like to figure out how I can best filter mail through a device with the quality of a SonicWall should MY SonicWall go out.
I thought that I could:
co-locate a second SonicWall somewhere that won't be subject to service outages, and have that SonicWall forward mail after filtering.
Partner with another SonicWall user.
Find a Spam Blocking service equal to SonicWall
OR - do something else I'm not yet aware exists.