Must Read: BGP Private AS Range
We all know that you have to use an AS number between 64512 and 65535 for private BGP autonomous systems, right? Well, we’re all wrong – the high end of the range is 65534, and Chris Parker wrote a nice blog post explaining the reasons behind that change.
I hope Job Snijders will never read the post written by Chris Parker or else he would pull his ears. He (Chris) forgot to mention large communities ...
4. Operational Considerations
Operators SHOULD NOT use these Last ASNs for any other purpose or as Private Use ASNs. Operational use of these Last ASNs could have undesirable results. For example; use of AS 65535 as if it were a Private Use ASN, may result in inadvertent use of BGP Well-known Community values [IANA.WK], causing undesirable routing behavior. """