Preventing domain spoofing emails

[Badaz52]

Hi,

 

As a bit of background we are a LA school who have an internal exchange 2013 server and we use a mail relay which sits at the LA end which provides some spam protection. In the past we have had numerous domain spoofing attempts some successful some unsuccessful but either way a real worry for security. After doing a bit of research I decided to enable Sender ID checks on our exchange server which instantly stopped the spoofing. The problem is we get the odd external email which receives the PRA not permitted message and gets dropped by our email server (why there is no quarantine option is beyond me!).

 

I am getting complaints that some emails are not being received and once I am given the domain name I put a rule in place to bypass the checks for certain senders that I know to be genuine, this is not good enough I am told even though as a general rule we all have a pretty good idea of who's emails we are expecting.

 

I just wondered if there is a better way to combat this? many web sources suggest that the issue is the senders themselves who have bad DNS records in the first place and we probably shouldn't accept emails from them if that is the case.

 

Any thoughts?

Edited October 21, 2015 by Badaz52

[Arthur]

An SPF "hard fail" DNS record should help prevent the spoofed e-mails.

 

http://blog.zensoftware.co.uk/2014/09/02/what-are-spf-sender-policy-framework-records-all-about/

[Badaz52]

Would this need to be setup on the LA's DNS servers or our own internal ones?

[Arthur]

Would this need to be setup on the LA's DNS servers or our own internal ones?

LA's DNS.

 

Since adding the SPF record to our domain we haven't had any of those fake [email protected] or [email protected] e-mails.