IOS-XR accepts extended communities and large communities by default.
You have to enable to send them, but not receive.
Here's a fun one.
By default Junos accepts extended communities on any BGP session (not just
on MP-BGP sessions like it's the default case on cisco -unless explicitly
Since most operators are not aware of this default Junos behaviour, one can
be importing routes to interesting places if one were so inclined.
-so yeah bleach unwanted communities on ingress (bleach those that would
interfere with the ones used by the AS internally -so called