Cisco Cisco Email Security Appliance C160 Mode D'Emploi

Use the Network > SMTP Routes page (or the 

smtproutes

 command) to construct 

routes. When you create a new route, you first specify the domain or partial 
domain for which you want to create a permanent route. You then specify 
destination hosts. Destination hosts can be entered as fully-qualified hostnames 
or as IP addresses. You can also specify a a special destination host of 

/dev/null

 

to drop the messages that match the entry. (So, in effect, specifying 

/dev/null

 for 

the default route is will ensure that no mail received by the appliance is ever 
delivered.) 

A receiving domain can have multiple destination hosts, each assigned a priority 
number, much like an MX record. The destination host with the lowest number 
identifies as the primary destination host for the receiving domain. Other 
destination hosts listed will be used as backup.

Destinations with identical priority will be used in a “round-robin” fashion. The 
round-robin process is based on SMTP connections, and is not necessarily 
message-based. Also, if one or more of the destination hosts are not responding, 
messages will be delivered to one of the reachable hosts. If all the configured 
destination hosts are not responding, mail is queued for the receiving domain and 
delivery to the destination hosts is attempted later. (It does not fail over to using 
MX records). 

When constructing routes using the 

smtproutes

 command in the CLI, you can 

prioritize each destination host by using 

/pri=

, followed by an integer between 

0

 

and 

65535

 to assign priority (

0

 is the highest priority) after the hostname or IP 

address. For example, 

host1.example.com/pri=0 

has a higher priority than 

host2.example.com/pri=10

. Separate multiple entries with commas.

You can define up to 40,000 routes. The final default route of 

ALL

 is counted as a 

route against this limit. Therefore, you can define up to 39,999 custom routes and 
one route that uses the special keyword 

ALL

.