Cisco Cisco Email Security Appliance C650 Guía Del Usuario
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Cisco AsyncOS 9.5 for Email User Guide
Chapter 7 Defining Which Hosts Are Allowed to Connect Using the Host Access Table (HAT)
Verifying Senders
Envelope Sender Verification
Malformed Envelope Senders:
Domain does not exist (NXDOMAIN):
Domain does not resolve (SERVFAIL):
Enabling Host DNS Verification via the CLI
To enable host DNS verification in the CLI, use the
listenerconfig > edit > hostaccess
command.
See the Cisco AsyncOS CLI Reference Guide for more information.
shows the types of unverified senders and the corresponding CLI setting:
Thu Aug 10 10:14:10 2006 Info: ICID 3248 Address: <user> sender rejected, envelope
sender domain missing
Wed Aug 9 15:39:47 2006 Info: ICID 1424 Address: <user@domain.com> sender rejected,
envelope sender domain does not exist
Wed Aug 9 15:44:27 2006 Info: ICID 1425 Address: <user@domain.com> sender rejected,
envelope sender domain could not be resolved
Table 7-10
Sender Group Settings and Corresponding CLI Values
Connecting Host DNS Verification
Equivalent CLI Setting
Connecting host PTR record does not exist in the DNS.
nx.domain
Connecting host PTR record lookup fails due to temporary DNS
failure.
failure.
serv.fail
Connecting host reverse DNS lookup (PTR) does not match the
forward DNS lookup (A)
forward DNS lookup (A)
not.double.verified