D-Link DFL-2500 - Manual (Page 152)

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 recognised 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 Mail attachment file content can be checked against its
filetype. A list of all filetypes checked can be found in
Appendix C, Checked MIME filetypes.
Anti-Virus Scanning The NetDefendOS Anti-Virus module can scan email
attachments searching for malicious code. This feature is
described fully in Section 6.4, “Anti-Virus Scanning”. The
available options are:
• Disable - Turn off scanning.
• Protect - Drop downloads that may contain a virus and
log.
• Audit - Log but do not drop downloads that may contain a
virus.
Anti-Virus Options
If Anti-Virus scanning is enabled then the following options can be used to control file scanning:
Anti-Virus Compression Rate Compressed files with a compression ration higher than the
specified value will trigger one of the following actions:
• Allow - Continue without the Anti-Virus scan.
• Scan - Continue scanning.
• Drop - Drop the file and end the transfer.
Include/Exclude Filetypes A list of filetypes which are to be included/excluded from
scanning can be specified.
6.2.7. SIP
Session Initiation Protocol (SIP) is an ASCII (UTF-8) text based signalling protocol used to
establish sessions between peers in an IP network. It is a request-response protocol that resembles
HTTP and SMTP. A session might consist of a Voice-Over-IP (VOIP) telephone call or it could be
a collaborative multi-media conference. Using SIP with VOIP means that telephony can become
another IP application which can integrate into other services.
SIP does not know about the details of a session's content and is only responsible for initiating,
terminating and modifying sessions. Sessions set up by SIP are typically used for the streaming of
audio and video over the Internet using the UDP protocol but they might also involve traffic based
on the TCP protocol. Although UDP based VOIP sessions are a common use, communication using
other protocols such as TCP or TLS might be involved in a session.
SIP is defined by the IETF standard RFC 3261 and is becoming popular as the standard for VOIP. It
is comparable to H.323 but a design goal with SIP is to make it more scalable that H.323. (For
6.2.7. SIP Chapter 6. Security Mechanisms
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