Cisco Cisco Email Security Appliance X1050 Guía Del Usuario
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Cisco IronPort AsyncOS 7.1 for Email Advanced Configuration Guide
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Chapter 2 Configuring Routing and Delivery Features
This feature also allows host “globbing.” If you specify a partial domain, such as
.example.com
, then any domain ending in
example.com
matches the entry. For
instance,
fred@foo.example.com
and
wilma@bar.example.com
both match the
mapping.
If a host is not found in the SMTP Routes table, an MX lookup is performed using
DNS. The result is not re-checked against the SMTP Routes table. If the DNS MX
entry for
DNS. The result is not re-checked against the SMTP Routes table. If the DNS MX
entry for
foo.domain
is
bar.domain
, any email sent to
foo.domain
is delivered to
the host
bar.domain
. If you create a mapping for
bar.domain
to some other host,
email addressed to
foo.domain
is not affected.
In other words, recursive entries are not followed. If there is an entry for
a.domain
to redirect to
b.domain
, and a subsequent entry to redirect email for
b.domain
to
a.domain
, a mail loop will not be created. In this case, email addressed to
a.domain
will be delivered to the MX host specified by
b.domain
, and conversely
email addressed to
b.domain
will be delivered to the MX host specified by
a.domain
.
The SMTP Routes table is read from the top down for every email delivery. The
most specific entry that matches a mapping wins. For example, if there are
mappings for both
most specific entry that matches a mapping wins. For example, if there are
mappings for both
host1.example.com
and
.example.com
in the SMTP Routes
table, the entry for
host1.example.com
will be used because it is the more specific
entry — even if it appears after the less specific
.example.com
entry. Otherwise,
the system performs a regular MX lookup on the domain of the Envelope
Recipient.
Recipient.
Default SMTP Route
You can also define a default SMTP route with the special keyword
ALL
. If a
domain does not match a previous mapping in the SMTP Routes list, it defaults to
being redirected to the MX host specified by the
being redirected to the MX host specified by the
ALL
entry.
When you print the SMTP Routes entries, the default SMTP route is listed as
ALL:
. You cannot delete the default SMTP route; you may only clear any values
entered for it.
Configure the default SMTP route via the Network > SMTP Routes page or the
smtproutes
command.