Cisco Cisco Email Security Appliance X1050 Guía Del Usuario
Chapter 3 Configuring Routing and Delivery Features
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Cisco IronPort AsyncOS 7.3 for Email Advanced Configuration Guide
OL-23081-01
Defining an SMTP Route
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
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.)
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.
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).
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.
SMTP Routes Limits
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
one route that uses the special keyword
ALL
.