This will be the first in a short series of articles I will be writing on mail flow troubleshooting. I wanted to start with a general article on how to narrow the scope of the mail flow issue. Mail flow issues typically fall into one of three categories.
- External mail is not coming in for all or some email.
- Internal mail is not going out to the Internet for all or some email.
- Internal mail flow is not working.
So before we start troubleshooting we need to determine which category to focus on. Occasionally you may see an issue that encompasses more than one of the categories above. If that is the case then it is best to start on internal mail flow.
When I start looking at a mail flow issue I like to start with a few questions.
- Are you having any issues sending or receiving emails to other users in your organization?
If the answer is yes, then this narrows down the scope of the issue tremendously. If the answer is no, then we know we need to start on internal mail flow troubleshooting.
- Are you having a problem with receiving emails from users outside your organization?
If the answer is yes, then you can focus on troubleshooting mail coming in from the Internet. If the answer is no, then the issue is likely mail going out to Internet is having issues.
- Are you having problems with users outside your organization receiving the emails your users are sending?
If the answer is yes, then you can focus on mail going out to other mail servers on the Internet.
So now that we have an understanding of how to narrow the scope of the issue, the next parts of this series will focus on troubleshooting each of the different categories.