Free MX EMail Server Backup Service
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Junk Email Filter is now offering a free MX backup service. If your email server goes offline our servers will accept your email, store it, and when your server comes back online it will deliver your email to you. And it's simple to activate. All you have to do is sign up, change your MX records, and it's ready to go.
Here's how it works. Suppose your domain is "example.com" and your MX record is "mail.example.com". You would add two more MX records as follows:
mail.example.com 10
mxbackup1.junkemailfilter.com 20
mxbackup2.junkemailfilter.com 30
That's all there is to it.
Implementation Details
In order for this to work we have to see our backup server in your MX records. DNS propagation often take several hours and because of that this service can't be used immediately upon changing your MX records. You should wait for several hours before testing.
Additionally we do forward callout testing to make sure your server is actually down and we don't pass email if your server is running. The reason for this is that we don't want to be a back door spam source for your domain. So if your server is running we will return a 4xx error so that email will retry to your server.
When your server comes back online our servers will detect it and automatically transfer backed up email. Depending on how long you were down and how much email we have for you it might take some time to deliver all your email. If you use grey listing or other rate limiting setting it could take even longer. Our system is not compatible with SPF so if you reject your good email based on SPF then you will lose it. SPF breaks email forwarding. All our servers however have RDNS set to *.junkemailfilter.com so you can white lists us to avoid bouncing your good email.
Although we try to do it right sometimes things don't work for any number of reason within and not within our control. We're not responsible for anything lost from using our service.
Why do I want it?
If your email server goes down and you don't have a backup incoming email can't be delivered. Most email servers will retry later but some email servers don't. If you are offline you could lose email from poorly configured email servers. (And there are a lot of them.) With backup MX servers if your servers are down the incoming email is delivered to our servers and we accept and store it. When your server comes back online all the pending email is transferred to you.
Besides being a backup email server you will also get some spam reduction. The spam reduction is somewhat effective even when your email server is working. This is especially effective on virus infected spambot spam. Many spam bots don't play by the rules. They figure that the backup email servers have less spam filtering than the main email server so they try to sneak the spam in the back door. However, our servers detect almost 100% of spambot spam and turns it away and thus significantly reduces the amount of spam you would otherwise get. This reduces the system load on your server because you no longer have to process and block these spam attempts. You might see as much as a 50% reduction in spam if your domain attracts a lot of spambot spam.
If you are using gray listing to reduce spam and experiencing delays on email delivery for new contacts our backup system might solve the problem. The senders will retry our servers immediately and we will pass the good email. Then we will deliver it to you immediately rather than having the sender wait the retry period. Since spam bots don't retry you still get the spam reduction capabilities of gray listing.
Why are we giving this away for free?
There are basically a few reasons that we are providing this service for free.
- Our main business is spam filtering. It is our hope that once you try our free backup MX service that you will be impressed and you will see some spam reduction and you'll want to upgrade to full spam filtering.
- Even though we don't make money on this we provide spam filtering to other customers and we have one of the largest and best RBL blacklists and whitelists on the planet. By being your backup we can detect more spambots and increase the size of out lists. Our black lists specializes in the fast and accurate detection of spambots. Although we don't have as big of a database as lists like SpamHaus, out detection methods are faster and we get the bad guys blocked quicker. So even if you never pay us a dime we are getting some benefit from it.
- We enjoy blocking spam and since we benifit from many free services on the Internet we feel that we give back by providing some free services to others. We have big fast servers and this doesn't really create a lot of load on our system.
Is this free offer going to last forever?
Nothing lasts forever. Enjoy it now while it's here and free. We will keep it free as long as it is in our interest to do so.
Returning the Favor
Some people ask, "What can I do to return the favor for this free service? We're not asking anything from you but if you put a link on your web site thanking us for the service then that will help us with our search ranking. Spreading the word always helps.
Is the spam filtering on the backup as good as your regular service?
No. First it only filters that spam that hits our servers. Since your server is the lowest MX record must spam will go directly to you. Of the spam that comes to us we only block the easy stuff. So most all the spambot spam will go away, but spam coming from Yahoo, Gmail, and Hotmail will for the most part pass right through. The good spam filtering you have to buy.
So - how do we sign up?
Signing up is easy and automatic. First we need you to join our announcement list so that we can let you know important issues and changes that we might make in the future. Then all you need to do is change your MX records.
It is important that these two be the highest numbered two MX records and it is very important not to make our MX the lowest numbered as that is for our spam filtering customers only and our MX Backup service requires your servers be the lowest numbered MX. Here is an example:
mail.example.com 10
mxbackup1.junkemailfilter.com 20
mxbackup2.junkemailfilter.com 30
Our service will accept and store incoming email for your domain(s) and forward the email to your primary email server. In order to be compatible with our system you should disable SPF checking because SPF breaks email forwarding. You should also whitelist and avoid rate limiting on email with a reverse IP address of *.junkemailfilter.com.
We store email up to 4 days and is rate limited to a reasonable amount so if you have a huge domain you should let us know for special arrangements. If your server goes offline then once your server comes back online we will usually detect it within minutes and transfer your email as fast as your server will accept it.
You should also experience some spam reduction even when your server is online. Many spammers try to send spam through the backup servers. Although we don't apply full filtering to our backup MX we do apply out light filtering rules and behavior traps and if you notice a drop in spam let us know about it. We think you should notice a significant difference. And if you like what you see you might be interested in full filtering.
If there are any problems let us know and we will fix it. Let us know when you activate this service.
Thank you for your interest in our services.
If you have any questions you can contact us at support@junkemailfilter.com.
What we would like in return
If you like this please spread the word and link to us. You might also want to consider our spam filtering service or use our black/white/yellow RBL lists. To keep our costs down we rely on word of mouth for advertising.
Technical Details
Our servers automatically detect your MX configuration and it verifies that we are in your high numbered MX but that we are also not lowest. That allows us to accept email for MX backup. The mxbackup1 entry points to a ring of servers in a variety of locations ready to accept and process email. The mxbackup2 MX record is really a dummy entry and it point to other servers that will always return a 421 temporary error after the DATA command. This is used for spam bot detection and feeds our blacklists after significant spam bot verification. Since spam bot don't retry the spam is essentially blocked because they don't come back to the real email servers.
Although we don't have full spam filtering on the servers we do have significant filtering on them. In fact our light filtering is better than a lot of commercial filtering. So spammer who tend to sneak through the backups servers are blocked and you will receive a significant spam reduction.
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