Forum Discussion

Zuke_254875's avatar
Zuke_254875
Icon for Altostratus rankAltostratus
Apr 03, 2019

Port range iRule

We have a requirement for a wildcard virtual server and to allow access to the application servers on port range between 30000 and 32768. When I apply the below iRule, I'm unable to reach the serve...
application delivery
iRules
LTM
Kai_Wilke's avatar
Kai_Wilke
Icon for MVP rankMVP
Apr 03, 2019

Hi Zuke,

the 

if
command has a build inmplicit expression. No need for the explicit 
[expr]
command.

when CLIENT_ACCEPTED {
    if { ( [TCP::client_port] < 30000 ) or ( [TCP::client_port] > 32768 ) } then {
        reject
    }
}

Just for learning purposes the iRules below will work too. But they are more complex and also slower, since you basically pipe the output of the explicit 

[expr]
command (0 or 1) to the implicit expression of the 
if
command...

when CLIENT_ACCEPTED {
    if { [expr { [TCP::client_port] < 30000 }] or [expr { [TCP::client_port] > 32768 }]} then {
        reject
    }
}
when CLIENT_ACCEPTED {
    if { [expr { ( [TCP::client_port] < 30000 ) or ( [TCP::client_port] > 32768 ) }] } then {
        reject
    }
}

Cheers, Kai