https://tools.ietf.org/html/rfc6996 64512 - 65534 inclusive – private 2 byte ASN 4200000000 - 4294967294 inclusive - private 4 byte ASN
configure
set protocols bgp 65000 parameters router-id 192.168.254.1
set protocols bgp 65000 neighbor 192.168.255.0 remote-as 65001
set protocols bgp 65000 neighbor 192.168.255.0 soft-reconfiguration inbound
set protocols bgp 65000 neighbor 192.168.255.0 default-originate
commit ; save