iRule to block\reject connections from Lync client

If Lync has a User-Agent that identifies it as Lync, you can write an iRule to drop the incoming connection. You may want to look at the HTTP_REQUEST or SERVER_CONNECTED events

when HTTP_REQUEST {
        if {[string tolower[HTTP::header "User-Agent"]] eq "lync user agent" } {
                drop
        }
}

Thank you for the response Cthulhucalling. I forgot to include that we are trying to reject connection from both Lync and Exchange clients. What do you think of this iRule below?

when HTTP_REQUEST { log local0.debug "Client IP:[IP::client_addr] attempt with user agent :[HTTP::header User-Agent]" if { [ string tolower [HTTP::header User-Agent]] contains "microsoft lync"} { drop log local0.info "Client IP:[IP::client_addr] has been blocked with user agent :[HTTP::header User-Agent]" } elseif { [ string tolower [HTTP::header User-Agent]] contains "microsoft outlook"} { drop log local0.info "Client IP:[IP::client_addr] has been blocked with user agent :[HTTP::header User-Agent]" } else { log local0.debug "Client IP:[IP::client_addr] attempt with user agent :[HTTP::header User-Agent] successful" } }

That way will work. The switch statement may make things simpler and faster.

when HTTP_REQUEST {
        switch -glob  [string tolower [HTTP::header "User-Agent"]]
        "microsoft lync*" -
        "microsoft outlook*" {
                log local0.info "Client IP:[IP::client_addr] has been blocked with user agent :[HTTP::header User-Agent]
                drop
        }
        default {
                log local0.debug "Client IP:[IP::client_addr] attempt with user agent :[HTTP::header User-Agent] successful"
        }
}

I received an error

01070151:3: Rule [ExternalSP_rule_drop_lync_exchange] error: line 2: [wrong args] [switch -glob [string tolower [HTTP::header "User-Agent"]]] line 3: [undefined procedure: microsoft lync] ["microsoft lync" -] line 4: [undefined procedure: microsoft outlook] ["microsoft outlook" { log local0.info "Client IP:[IP::client_addr] has been blocked with user agent :[HTTP::header User-Agent] drop }] line 8: [undefined procedure: default] [default { log local0.debug "Client IP:[IP::client_addr] attempt with user agent :[HTTP::header User-Agent] successful" }]

when HTTP_REQUEST {
        switch -glob  [string tolower [HTTP::header "User-Agent"]] {
                "microsoft lync" -
                "microsoft outlook*" {
                        log local0.info "Client IP:[IP::client_addr] has been blocked with user agent :[HTTP::header User-Agent]"
                        drop
                }
                default {
                        log local0.debug "Client IP:[IP::client_addr] attempt with user agent :[HTTP::header User-Agent] successful"
                }
        }
}