Difference between revisions of "SecureXL Mechanism"

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SecureXL Mechanism

Solution ID: sk32578 Product: SecureXL Version: All Platform / Model: All Date Created: 15-Feb-2007 Last Modified: 26-Mar-2014

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Traffic acceleration:

When SecureXL is enabled, all traffic should be accelerated, except traffic that matches the following conditions: The first packets of any new TCP session, unless a "template" exists. The first packet of any new UDP session. All traffic that matches a service that uses a Resource. Certain traffic that matches a service that is inspected by a SmartDefense/IPS or Web Intelligence feature. For example, traffic on which SSH protections are activated is not accelerated. For more details, refer to sk42401 (Factors that adversely affect performance in SecureXL). All traffic that is supposed to be dropped or rejected, according to the rule base. All traffic that matches a rule, whose source or destination is the Security Gateway itself. All traffic that matches a rule with a Security Server (e.g., Authenication, Anti-Virus, URL Filtering, Anti-Spam). All traffic that matches a rule with User Authentication or Session Authentication. Non-TCP/UDP/GRE/ESP traffic (including ICMP traffic). CIFS traffic. IPv6 traffic. All multicast traffic. All fragmented traffic. All traffic with IP options. Connections that will be matched for ISP Redundancy (inbound/outbound interface is one of the interfaces configured for ISP Redundancy). TCP RST packets, when the "Spoofed Reset Protection" feature is activated. When using ClusterXL in Load Sharing mode with 'Sticky Decision Function'. Traffic that violates stateful inspection paradigm, or that is suspected to be spoofed.

Connection establishment acceleration ("templates" mechanism):

In order to enhance connection establishment acceleration, a mechanism attempts to "group together" all connections that match a particular service and whose sole discriminating element is the Source Port. This type of "grouping" enables even the very first packets of a TCP handshake to be accelerated. This is very useful on short connections, in which the percentage of TCP handshake traffic is very high. The very first packets of the first connection on the same service will be forwarded to the Security Gateway's kernel, which will then create a "template" of the connection and notify the SecureXL device. Any subsequent TCP connections established on the same service (where only the source port is different) will already be accelerated (as well as any other traffic, of course).

There are several conditions that will prevent a template from being created:

   Connections that cannot be discriminated ONLY by the source port cannot be templated.

   NATed traffic cannot be templated.

   VPN traffic cannot be templated.

   Complex connections (FTP, H323, SQL, etc.) cannot be templated.

   Non-TCP/Non-UDP traffic (including ICMP traffic) cannot be templated.

   The following rules will prevent a Connection Template from being created.

   All subsequent rules below such rules will not be templated as well, regardless of the rule. It is advised that all rules that can be templated, be placed at the top of the rule base (unless of course, this will violate other optimization considerations):

       Rule with service 'Any' (resolved in R75.40 and above)

       Rule with a service that has a 'handler' (where a specific protocol is chosen in 'Protocol Type' field - instead of 'None' ; go to service object - right-click - Edit... - Advanced... - Protocol Type:).

       Rules with the following objects:

           Time object

           Port range object (resolved in R75.40 and above)

           Dynamic object

           Domain object

       Rules with "complex" services (i.e., services that have anything specified in the "Match" field, or "Enable reply from any port" of their "Advanced" section or Source Port is defined).

       Rules with RPC/DCOM/DCE-RPC services.

       Rules with Client Authentication or Session Authentication.

       When SYN Attack (SYN Defender), or Small PMTU features are activated in SmartDefense/IPS.