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To clean out the dnsbl cache for my_smtp_alg and to reset all its statistical counters, the following
command option can be used:
gw-world:/> dnsbl my_smtp_alg -clean
Tip: DNSBL servers
A list of DNSBL servers can be found at:
http://en.wikipedia.org/wiki/Comparison_of_DNS_blacklists.
6.2.6. The POP3 ALG
POP3 is a mail transfer protocol that differs from SMTP in that the transfer of mail is directly from a
server to a user's client software.
POP3 ALG Options
Key features of the POP3 ALG are:
Block clients from sending USER
and PASS command
Block connections between client and server that send the
username/password combination as clear text which can be
easily read (some servers may not support other methods than
this).
Hide User
This option prevents the POP3 server from revealing that a
username does not exist. This prevents users from trying
different usernames until they find a valid one.
Allow Unknown Commands
Non-standard POP3 commands not recognized by the ALG
can be allowed or disallowed.
Fail Mode
When content scanning find bad file integrity then the file can
be allowed or disallowed.
Verify MIME type
The content of an attached file can be checked to see if it
agrees with its stated filetype. A list of all filetypes that are
verified in this way can be found in Appendix C, Verified
MIME filetypes. This same option is also available in the
HTTP ALG and a fuller description of how it works can be
found in Section 6.2.2, “The HTTP ALG”.
Block/Allow filetype
Filetypes from a predefined list can optionally be blocked or
allowed as mail attachments and new filetypes can be added
to the list. This same option is also available in the HTTP
ALG and a fuller description of how it works can be found in
Section 6.2.2, “The HTTP ALG”.
Anti-Virus Scanning
The NetDefendOS Anti-Virus subsystem can optionally scan
email attachments searching for malicious code. Suspect files
6.2.6. The POP3 ALG Chapter 6. Security Mechanisms
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