Cisco Cisco Email Security Appliance X1070 Troubleshooting Guide
Can I use the ESA without DNS?
Document ID: 118009
Contributed by Jackie Fleming and Enrico Werner, Cisco TAC
Engineers.
Engineers.
Jul 18, 2014
Contents
Question:
Question:
Can I use the ESA without DNS?
While it is possible to run the ESA without DNS access, it is not recommended or supported. A configuration
without DNS is difficult to set up and would disable access to valuable features. For example, SenderBase
scores would be unavailable, and no domain information would be included in the logs or Reporting. In this
case, all configurations would have to be entered as IP addresses and a proxy server may be needed to retrieve
updates. In order to deliver to the Internet in general, another server that does have DNS access would have to
act as a gateway for the ESA. This type of configuration would limit the ESA to applications where mail is
only flowing to a few servers and the ESA is simply used to perform content scanning.
without DNS is difficult to set up and would disable access to valuable features. For example, SenderBase
scores would be unavailable, and no domain information would be included in the logs or Reporting. In this
case, all configurations would have to be entered as IP addresses and a proxy server may be needed to retrieve
updates. In order to deliver to the Internet in general, another server that does have DNS access would have to
act as a gateway for the ESA. This type of configuration would limit the ESA to applications where mail is
only flowing to a few servers and the ESA is simply used to perform content scanning.
Updated: Jul 18, 2014
Document ID: 118009