D-Link DFL-260-IPS-12 Product Manual - Page 478

Setting Up SLB_SAT Rules, Note: FwdFast rules should not be used with SLB

Page 478 highlights

10.4.6. Setting Up SLB_SAT Rules Chapter 10. Traffic Management 10.4.6. Setting Up SLB_SAT Rules The key component in setting up SLB are IP rules that have SLB_SAT as the action. The steps that should be followed for setting up such rules are: 1. Define an IP address object for each server for which SLB is to enabled. 2. Define an IP address group object which includes all these individual objects. 3. Define an SLB_SAT rule in the IP rule set which refers to this IP address group and where all other SLB parameters are defined. 4. Define a further rule that duplicates the source/destination interface/network of the SLB_SAT rule that permits the traffic through. This could be one rule or a combination of rules using the actions: • Allow • NAT Note: FwdFast rules should not be used with SLB In order to function, SLB requires that the NetDefendOS state engine keeps track of connections. FwdFast IP rules should not be used with SLB since packets that are forwarded by these rules are under state engine control. The table below shows the rules that would be defined for a typical scenario of a set of webservers behind the NetDefend Firewall for which the load is being balanced. The Allow rule allows external clients to access the webservers. Rule Name WEB_SLB WEB_SLB_ALW Rule Type SLB_SAT Allow Src Interface any any Src Network all-nets all-nets Dest Interface core core Dest Network ip_ext ip_ext If there are clients on the same network as the webservers that also need access to those webservers then an NAT rule would also be used: Rule Name WEB_SLB WEB_SLB_NAT WEB_SLB_ALW Rule Type SLB_SAT NAT Allow Src Interface any lan any Src Network all-nets lannet all-nets Dest Interface core core core Dest Network ip_ext ip_ext ip_ext Note that the destination interface is specified as core, meaning NetDefendOS itself deals with this. The key advantage of having a separate Allow rule is that the webservers can log the exact IP address that is generating external requests. Using only a NAT rule, which is possible, means that webservers would see only the IP address of the NetDefend Firewall. Example 10.3. Setting up SLB In this example server load balancing is to be done between 2 HTTP webservers which are situated behind the NetDefend Firewall. The 2 webservers have the private IP addresses 192.168.1.10 and 192.168.1.11 respectively. The default SLB values for monitoring, distribution method and stickiness are used. A NAT rule is used in conjunction with the SLB_SAT rule so that clients behind the firewall can access the webservers. An Allow rule is used to allow access by external clients. 478

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10.4.6. Setting Up
SLB_SAT
Rules
The key component in setting up SLB are IP rules that have
SLB_SAT
as the action. The steps that
should be followed for setting up such rules are:
1.
Define an IP address object for each server for which SLB is to enabled.
2.
Define an IP address group object which includes all these individual objects.
3.
Define an
SLB_SAT
rule in the IP rule set which refers to this IP address group and where all
other SLB parameters are defined.
4.
Define a further rule that duplicates the source/destination interface/network of the
SLB_SAT
rule that permits the traffic through. This could be one rule or a combination of rules using the
actions:
Allow
NAT
Note: FwdFast rules should not be used with SLB
In order to function, SLB requires that the NetDefendOS state engine keeps track of
connections.
FwdFast
IP rules should not be used with SLB since packets that are
forwarded by these rules are under state engine control.
The table below shows the rules that would be defined for a typical scenario of a set of webservers
behind the NetDefend Firewall for which the load is being balanced. The
Allow
rule allows external
clients to access the webservers.
Rule Name
Rule Type
Src Interface
Src Network
Dest Interface
Dest Network
WEB_SLB
SLB_SAT
any
all-nets
core
ip_ext
WEB_SLB_ALW
Allow
any
all-nets
core
ip_ext
If there are clients on the same network as the webservers that also need access to those webservers
then an
NAT
rule would also be used:
Rule Name
Rule Type
Src Interface
Src Network
Dest Interface
Dest Network
WEB_SLB
SLB_SAT
any
all-nets
core
ip_ext
WEB_SLB_NAT
NAT
lan
lannet
core
ip_ext
WEB_SLB_ALW
Allow
any
all-nets
core
ip_ext
Note that the destination interface is specified as
core
, meaning NetDefendOS itself deals with this.
The key advantage of having a separate
Allow
rule is that the webservers can log the exact IP
address that is generating external requests. Using only a
NAT
rule, which is possible, means that
webservers would see only the IP address of the NetDefend Firewall.
Example 10.3. Setting up SLB
In this example server load balancing is to be done between 2 HTTP webservers which are situated behind the
NetDefend
Firewall.
The
2
webservers
have
the
private
IP
addresses
192.168.1.10
and
192.168.1.11
respectively. The default SLB values for monitoring, distribution method and stickiness are used.
A
NAT
rule is used in conjunction with the
SLB_SAT
rule so that clients behind the firewall can access the
webservers. An
Allow
rule is used to allow access by external clients.
10.4.6. Setting Up SLB_SAT Rules
Chapter 10. Traffic Management
478