D-Link DFL-260 Product Manual - Page 351
Protocols Handled by SAT, 7.4.6. Multiple SAT Rule Matches
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7.4.5. Protocols Handled by SAT Chapter 7. Address Translation Port Translation (PAT) (also known as Port Address Translation) can be used to modify the source or destination port. # Action Src Iface 1 SAT any Src Net all-nets Dest Iface Dest Net Parameters wan wwwsrv_pub TCP 80-85 SETDEST 192.168.0.50 1000 This rule produces a 1:1 translation of all ports in the range 80 - 85 to the range 1080 - 1085. • Attempts to communicate with the web servers public address - port 80, will result in a connection to the web servers private address - port 1080. • Attempts to communicate with the web servers public address - port 84, will result in a connection to the web servers private address - port 1084. Note: A custom service is needed for port translation In order to create a SAT rule that allows port translation, a Custom Service object must be used with the rule. 7.4.5. Protocols Handled by SAT Generally, static address translation can handle all protocols that allow address translation to take place. However, there are protocols that can only be translated in special cases, and other protocols that simply cannot be translated at all. Protocols that are impossible to translate using SAT are most likely also impossible to translate using NAT. Reasons for this include: • The protocol cryptographically requires that the addresses are unaltered; this applies to many VPN protocols. • The protocol embeds its IP addresses inside the TCP or UDP level data, and subsequently requires that, in some way or another, the addresses visible on IP level are the same as those embedded in the data. Examples of this include FTP and logons to NT domains via NetBIOS. • Either party is attempting to open new dynamic connections to the addresses visible to that party. In some cases, this can be resolved by modifying the application or the firewall configuration. There is no definitive list of what protocols that can or cannot be address translated. A general rule is that VPN protocols cannot usually be translated. In addition, protocols that open secondary connections in addition to the initial connection can be difficult to translate. 7.4.6. Multiple SAT Rule Matches NetDefendOS does not terminate the rule set lookup upon finding a matching SAT rule. Instead, it continues to search for a matching Allow, NAT or FwdFast rule. Only when it has found such a matching rule does NetDefendOS execute the static address translation. Despite this, the first matching SAT rule found for each address is the one that will be carried out. The phrase "each address" above means that two SAT rules can be in effect at the same time on the same connection, provided that one is translating the sender address whilst the other is translating the destination address. # Action 1 SAT 2 SAT Src Iface any lan Src Net all-nets lannet Dest Iface core all-nets Dest Net wwwsrv_pub Standard Parameters TCP 80-85 SETDEST 192.168.0.50 1080 SETSRC pubnet 351