Solved

Keeping Emails If Server Offline

Posted on 2013-02-05
5
188 Views
Last Modified: 2013-02-05
I'm thinking of hosting a mail server behind a Dynamic DNS service.
1) Is that possible?
2) If there any failsafe in smtp that allows for incoming emails to be kept if the mail server is down?
0
Comment
Question by:Silas2
  • 3
  • 2
5 Comments
 
LVL 7

Expert Comment

by:Beneford
ID: 38855033
You're likely to lose emails if the connection goes down and is then reconnected with a different IP address (which, on a dynamic IP circuit is very likely).

There is a TTL (time to live) on the dns lookup, and a mail server trying to connect to you will assume the IP Address remains valid for that TTL period (even 10 minutes is too long for what you need).
If you do drop the connection the mail server may succeed in sending email addressed to you to another server (which just happens to have connected with your old ip address), and that server just might do something with it.
If you want to be secure and not lose emails, you need a fixed ip address.

If your system is not highly available (you need to define how high it needs to be - in-office or at-home broadband/fibre pretty reliable, but it's not 100%) you probably want a backup Mail Exchanger that will store email while your primary server is down and forward them when you come back up.

Some ISPs provide this service along with a hosted server (I have two cpanel hosted servers that do the job).
0
 

Author Comment

by:Silas2
ID: 38855416
Thanks for that. Regarding "...you probably want a backup Mail Exchanger that will store email while your primary server is down and forward them when you come back up...." how would you enable that to take over receipt automatically?
0
 
LVL 7

Expert Comment

by:Beneford
ID: 38855439
Define two MX records with different priorities.
The lowest priority is for your primary server, and a higher priority for the backup server.
A mail server will normally locate your lowest priority server and use that; if it's not available, the higher priority server will be used.
If correctly configured, the backup mail exchanger will also check for the availability of the higher-priority server and forward mail to then when it becomes available.
0
 

Author Comment

by:Silas2
ID: 38855472
I've just configured an email server (with postfix) would the back mail servers need to be setup with the same ? i dunno what, settings? to take the mail due for the first server?
0
 
LVL 7

Accepted Solution

by:
Beneford earned 250 total points
ID: 38855518
0

Featured Post

How your wiki can always stay up-to-date

Quip doubles as a “living” wiki and a project management tool that evolves with your organization. As you finish projects in Quip, the work remains, easily accessible to all team members, new and old.
- Increase transparency
- Onboard new hires faster
- Access from mobile/offline

Join & Write a Comment

Import PST to Exchange using Power Shell new-mailboximportrequest command, you can simply import the PST file into Exchange mailbox or archived. To know How to import PST into Exchange  2013 read the complete article.
This process describes the steps required to Import and Export data from and to .pst files using Exchange 2010. We can use these steps to export data from a user to a .pst file, import data back to the same or a different user, or even import data t…
Familiarize people with the process of retrieving data from SQL Server using an Access pass-thru query. Microsoft Access is a very powerful client/server development tool. One of the ways that you can retrieve data from a SQL Server is by using a pa…
In this video we show how to create a Distribution Group in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Recipients >>…

757 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

22 Experts available now in Live!

Get 1:1 Help Now