Solved

Fail Over DNS

Posted on 2011-02-16
6
510 Views
Last Modified: 2012-05-11
What is the option if a server fails at one location and you bring it up at another location, is there a way to have a fail over dns record for e-mail? I am guessing that would just simply be a higher number in the MX record, but is there a service or way of setting it up if one MX was not responding it would fail over to the other server?
0
Comment
Question by:patrickschuler
6 Comments
 
LVL 33

Expert Comment

by:Busbar
Comment Utility
you can setup another MX as you said with a higher priority on your DNS server, mail servers will try the first if not it will pickup the second one, this is done automatically.
0
 
LVL 4

Expert Comment

by:andreizz
Comment Utility
I think it does that automatically, you just have to add on the primary server the secondary mail server dns record, like you said with higher MX number.
0
 
LVL 35

Expert Comment

by:Ernie Beek
Comment Utility
Just have a second MX record with a higher preference, just like this:

google.com      MX preference = 100, mail exchanger = google.com.s9a1.psmtp.com
google.com      MX preference = 200, mail exchanger = google.com.s9a2.psmtp.com
google.com      MX preference = 300, mail exchanger = google.com.s9b1.psmtp.com
google.com      MX preference = 400, mail exchanger = google.com.s9b2.psmtp.com


First, the lowest preference will be tried (100). If that doesn't respond the second lowest will be tried. If that doesn't respond, etc.
0
Free Trending Threat Insights Every Day

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

 
LVL 20

Accepted Solution

by:
thehagman earned 500 total points
Comment Utility
For a server move (chacng of IP from 11.22.33.44 to 55.66.77.88) I suggest

yourdomain.com  MX   10  mail.yourdomain.com
yourdomain.com  MX   20  new-mail.yourdomain.com
yourdomain.com  MX   100  fallback-mail.yourdomain.com
mail.yourdomain.com  A  11.22.33.44
new-mail.yourdomain.com  A  55.66.77.88
fallback-mail.yourdomain.com  A =??.??.??.??   (should be online during the whole move process)

Once the move is complete, you may sort things out, e.g. remove all references to old IP and rename new-mail t mail.
In principle you *could* leave old data in DNS, but: Mail transfer would slow down as everybody would first try the obsolete server; and if you hand back the old IP address range, someone else may obtain the IP address and might catch your mail

ANother hint: You may need to be careful if you use the same server for outbound mail as then hostname and EHLO greeting should match (and should match reverse DNS)

You may even try

yourdomain.com  MX   10  mail.yourdomain.com
yourdomain.com  MX   100  fallback-mail.yourdomain.com
mail.yourdomain.com  A  11.22.33.44
mail.yourdomain.com  A  55.66.77.88
fallback-mail.yourdomain.com  A =??.??.??.??   (should be online during the whole move process)


Actually, you may be able to do this without fallback mail server as sending mail servers will themselves buffer mails for a while (typically days) and retry. A fallback mail server does however reduce the possibility of annoyance at the sender side.
0
 
LVL 39

Expert Comment

by:Krzysztof Pytko
Comment Utility
If it's domain environment and you have DCs with DNS installed and your DNS zone is AD integrated then that's no problem. Your DNS server is up and running if one of them would fail, each of your DNS server contain read/write DNS zone(s). Just remember that you have to specify in NIC's properties of each statically configured machine 2 or more DNS servers IP for failover. Also in DHCP server modify option no 006 to provide 2 DNS server to your DHCP clients. That's all

Regards,
Krzysztof
0
 

Expert Comment

by:PacketExchanger
Comment Utility
You can use a GEOdns service, and route your mx through a load balance, failover solution, so in case your mail server looses connectivity or services are failing, then the load balancer should have an active failover rule which will change request from going to the bad location, you can also use this to distribute the load evenly for high request.


check www.3crowd.com        they can provide this service for you


0

Featured Post

Free camera licenses with purchase of My Cloud NAS

Milestone Arcus software is compatible with thousands of industry-leading cameras for added flexibility. Upon installation on your My Cloud NAS, you will receive two (2) camera licenses already enabled in the software. And for a limited time, get additional camera licenses FREE.

Join & Write a Comment

Exchange server is not supported in any cloud-hosted platform (other than Azure with Azure Premium Storage).
Find out how to use Active Directory data for email signature management in Microsoft Exchange and Office 365.
This tutorial will walk an individual through setting the global and backup job media overwrite and protection periods in Backup Exec 2012. Log onto the Backup Exec Central Administration Server. Examine the services. If all or most of them are stop…
To add imagery to an HTML email signature, you have two options available to you. You can either add a logo/image by embedding it directly into the signature or hosting it externally and linking to it. The vast majority of email clients display l…

771 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now