iRule to reject a specific activesync DeviceId

Sure. You're very close. I don't see the need for the priority so I've dropped that. I've changed 'reject' to 'drop' so no TCP RST is sent, saving a few more CPU cycles and a tiny bit of memory. Just ensure the case of the header and it's value are correct (or alternatively use 'string tolower' to make everything lower case).

when HTTP_REQUEST {
 if { [HTTP::header value "DeviceId"] equals "SamsungXYZ123" } {
  drop } 
}

Hmmm. It's not working. I wonder if it's a case sensitivity issue that you mentioned. Would you mind explaining the 'string tolower option? Is that a checkbox in the GUI? or part of the iRule?

Part of the iRule. It seems the HTTP header command is case insensitive about the header name but not it's value. If you ensure the string your matching against is lower case we can avoid doing the conversion to lower case twice. I've added some logging too which you can remove or comment out later;

when HTTP_REQUEST {
 if { [string tolower [HTTP::header value "DeviceId"]] equals "samsungxyz123" } {
  drop
  log local0. "Dropped a request from [HTTP::header value "DeviceId"]"
 } 
}

You may also want to change the equals to contains if the specific user-agent isn't exactly samsungxyz123.

Aaron

Hi it is an irule command.