SMTP Relay
For this message source setting, traffic is received via an SMTP relay from a SEG. You will have defined the IP addresses you expect email from in the initial Secure Email Threat Defense setup.
The exact steps to direct mail from your SEG will depend on your system. To receive incoming email relayed from your SEG/MTA, complete the following:
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Set up connection limits for all connections made to Secure Email Threat Defense:
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Messages are accepted over TLS 1.2 only
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Maximum messages per connection is 10
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For Secure Email Threat Defense to be able to process Relay messages, the Sender IP needs to be present as a header in the email. Add the following headers:
X-CSE-ClientIP - IP of the sender who sent the mail to the SEG\MTA.
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Redirect messages to one of the following hosts based on your Region/Environment.
Table 1. MX Record Settings by Region
| Region/Environment | DNS Record |
|---|---|
| North America | mx.us.etd.cisco.com |
| Europe | mx.eu.etd.cisco.com |
| India | mx.ap.etd.cisco.com |
| Australia | mx.au.etd.cisco.com |
| United Arab Emirates | mx.ae.etd.cisco.com |
| Beta | mx.beta.etd.cisco.com |
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Configure your domain to enable Secure Email Threat Defense to deliver incoming email to mailboxes. IP addresses for each region are mentioned below, however we recommend retrieving the updated list of IPs using the corresponding host name
Example: dig host.<region>.etd.cisco.com retrieves the corresponding IPs for the region.
Table 2. Regional Host Names and IPs
| Region/Environment | Host Name | IPs |
|---|---|---|
| North America | host.us.etd.cisco.com |
|
| Europe | host.eu.etd.cisco.com |
|
| India | host.in.etd.cisco.com |
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| Australia | host.au.etd.cisco.com |
|
| United Arab Emirates | host.ae.etd.cisco.com |
|
| Beta | host.beta.etd.cisco.com |
|