Fortinet FortiWAN, Handbook

Page: 224 / 311

Optional Services Persistent Routing
Source : Established connections from the specified source will be matched (See " Using the web
UI ").
Action : Do PR: the matched connections will be routed persistently.
No PR: the matched connections will NOT be routed persistently. (The Default)
L : Check to enable logging: Whenever the rule is matched, system will record the event to log
file.
IPv4/IPv6 IP Pair Rules
Sets persistent routing rules on IPv4/IPv6 addresses. Enable this function, and all connections established from the
source IPv4/IPv6 to destination IPv4/IPv6 specified below are governed by IPv4/IPv6 IP Pair Rules.
E : Check the box to enable the rule.
When :
Options: Busy hour, Idle hour, and All-Time (See "
Busyhour Settings
").
Source :
Established connections from the specified source will be matched (See "
Using the web
UI
").
Destination : The connections to the specified destination will be matched. This field is the same as the
“Source” field, except it matches packets with the specified destination (See "
Using the web
UI
").
Action :
Do PR: the matched connections will be routed persistently. (The Default)
No PR: the matched connections will NOT be routed persistently.
L : Check to enable logging: Whenever the rule is matched, system will record the event to log
file.
Persistent routing is often used when destination servers check source IP. The function is performed on most secure
connections (e.g. HTTPS and SSH). To prevent the connections from being dispatched over a diverse range of WAN
links, persistent routing serves the best solution for maintaining connections over a fixed WAN link.
See below for how auto-routing is related to persistent-routing:
Once a connection is established, auto-routing rules are applied to determine the WAN link to be used.
Subsequent connections with the same destination and source pair obey the rules formulated in the persistent routing
table. Note that the device will consult the rule table whenever established connections are to be sent to new
destinations.
Auto-routing will be reactivated once in persistent routing the interval between two successive connections are longer
than timeout period. A second connection will be considered as a "new" one. Then auto-routing will secure the
connection to go through a different WAN link.
Example 1
The persistent routing policies to be established accordingly:
224 FortiWAN Handbook
Fortinet Technologies Inc.