Users Guide

Table Of Contents
Dell PowerConnect ArubaOS 5.0 | User Guide External Services Interface | 573
Peer Controllers
As an alternative, consider a topology where multiple controllers share one or more ESI servers (see “Peer
Controllers” on page573).
Figure 123 Peer Controllers
In this scenario, several controllers (master and local) are defined in the same syslog parser domain and are also
configured to act as peers. From the standpoint of the ESI servers—because there is no good way of determining
from which controller a given user came—the event is flooded out to all controllers defined as peers within this
ESI parser domain. The corresponding controller holding the user entry acts on the event, while other controllers
ignore the event.
Syslog Parser Rules
The user creates an ESI rule by using characters and special operators to specify a pattern (regular expression)
that uniquely identifies a certain amount of text within a syslog message. (Regular expression syntax is described
in “Basic Regular Expression Syntax” on page593.) This “condition” defines the type of message and the ESI
domain to which this message pertains. The rule contains three major fields:
z Condition: The pattern that uniquely identifies the syslog message type.
z User: The username identifier. It can be in the form of a name, MAC address, or IP address.
z Action: The action to take when a rule match occurs.
Once a condition match has been made, no further rule-matching will be made. For the rule that matched, only
one action can be defined.
After a condition match has been made, the message is parsed for the user information. This is done by specifying
the target region with the regular expression (REGEX) regex() block syntax. This syntax generates two blocks:
The first block is the matched expression; the second block contains the value inside the parentheses. For
username matching, the focus is on the second block, as it contains the username.
Condition Pattern Matching
The following description uses the Fortigate virus syslog message format as an example to describe condition
pattern matching. The Fortigate virus syslog message takes the form:
arun_002
Master Controller
10.0.0.1
Fortinet Server
30.0.0.2
Fortinet Server
30.0.0.1
Fortinet Server
30.0.0.3
Peer Controllers
ESI Server Group
AP
Wireless Client
Jack
Wireless Client
Joe
Local Controller
20.0.0.1
AP