Simple Mail Transfer Protocol - D-Link NetDefend DFL-210 User Manual

6.2.4. Simple Mail Transfer Protocol

are no rules disallowing or allowing the same kind of ports/traffic before these rules. The service in use is the "ftp-
outbound", which should be using the ALG definition "ftp-outbound" as described earlier.
Allow connections to ftp-servers on the outside:
1. Go to Rules > IP Rules > Add > IPRule
2. Now enter:
• Name: Allow-ftp-outbound
• Action: Allow
• Service: ftp-outbound
3. For Address Filter: enter:
• Source Interface: lan
• Destination Interface: wan
• Source Network: lannet
• Destination Network: all-nets
4. Click OK.
Rules (Using Private IPs). If the firewall is using private IP's, the following NAT rule need to be added instead:
1. Go to Rules > IP Rules > Add > IPRule
2. Now enter:
• Name: NAT-ftp-outbound
• Action: NAT
• Service: ftp-outbound
3. For Address Filter enter:
• Source Interface: lan
• Destination Interface: wan
• Source Network: lannet
• Destination Network: all-nets
4. Check Use Interface Address.
5. Click OK.
6.2.4. Simple Mail Transfer Protocol
Simple Mail Transfer Protocol (SMTP) is a text based protocol that is used for transferring email
over the internet.
Key features of the SMTP ALG are:
• Rate Limiting - A maximum allowable rate of email messages can be specified.
• Email address blacklisting - A blacklist of email addresses can be specified so that mail from
those addresses is blocked.
• Email address blacklisting - A whitelist of email addresses can be specified so that mail from
those addresses is allowed to pass by the ALG.
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Chapter 6. Security Mechanisms