Cisco Cisco Email Security Appliance X1070 Mode D'Emploi

Choose from one of the following methods for connecting 
to the call-ahead server:

Use Delivery Host. Select this option to specify that 
the host for the delivery email address is used for the 
SMTP call-ahead query. For example, if the mail 
recipient address is recipient@example.com, the 
SMTP query is executed against the SMTP server 
associated with example.com. If you have configured 
SMTP routes or LDAP routing queries, these routes are 
used to determine the SMTP server to query. For 
details about configuring LDAP routing queries, see 

.

Static Call-Ahead Server. Use this option to create a 
static list of call-ahead servers to query. You may want 
to use this option if you do not expect the names and 
locations of the call-ahead servers to change often. 
When you use this option, the Email Security 
appliance queries the hosts in a round-robin fashion, 
starting with the first static call-ahead server listed. 

Note that when you choose the static 
call-ahead server type, no SMTP routes are 
applied to the query. Instead an MX lookup is 
performed, and then an A lookup is performed 
on the hosts to obtain the call-ahead IP 
addresses for the static servers. 

If you choose to use the static call-ahead server type, enter 
a list of host and port combinations in this field. List the 
server and port using the following syntax:

ironport.com:25

Separate multiple entries with a comma.