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 ...
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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. """