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Cisco Employee

Why is email not getting an SBRS score "SBRS None"

Hi Folks,

Lots of SPAM is getting through and I noticed in the mail_logs and also in Message Tracking that both legitimate email and SPAM email have no SBRS score. After I changed the configs to point to a public DNS things started to work again. Why is that? My DNS server is resolving things just fine, why would changing the config to point to a public DNS server make things start working again. I am running the latest shipping code and IPAS features are enabled.

Thanks for any input.

Everyone's tags (4)
Cisco Employee

Why is email not getting an SBRS score "SBRS None"

It is possible your DNS servers were not answering fast enough. If you need further check, I recommend opening a support ticket and asking DNS admin to review performance/logs at the DNS servers.

By the way, the use of Internet root DNS servers is not only default but, also, recommended.




Re: Why is email not getting an SBRS score "SBRS None"

I wonder this answer is correct or not. I doubt the way "recommended" to set root servers in ironport.

First, the root servers do not answer these queries for anyone, it only handles a handful of 2nd level top domains.

Second, it does come across to me that google dns (or _is_ faster than most small ISP due to DNS Anycast (a closer one is supposed queried) _AND_ much better bandwidth diversity and connectivites from Google. this might be true for individual pc clients, but not always true. e.g. the "network" path to may be long enough or can have many point of failure.

For coporation and bussiness operation, usually private DNS internal view are needed and these needed to be within the perimeter of the corporation.

And due to recent securities concerns, no one want to leak any information (such as DNS queries?) to Google.

Cisco Employee

Re: Why is email not getting an SBRS score "SBRS None"


The recommended setting is to use Internet Root servers. If that represents a risk or a policy vialotion to your company then, of course, you cannot use the recommended setting. This is why the device allows Internal DNS servers to be configure. If your device is experiencing the SBRS none issue and using private DNS servers, then please engage your DNS server admin and our support team.



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