When configuring the hide local AS feature, the external peers see both the local-AS and the real AS number prepended in front of the AS_PATH. Sometimes it is desirable to completely hide the “real” AS number (the one configured via the router bgp command). To accomplish this, use the no-prepend replace-as parameters to the local-as command. This combination will replace the real AS number with the one specified in the local-as command. The respective neighbor will be tricked into thinking that all routers are received from the AS number configured with the local-as command, because this number will appear in the AS_PATH and BGP OPEN message
R5(config-router)#neighbor 15.1.1.1 local-as 500 no-prepend replace-as
DUAL-AS
The dual-as keyword is used to configure the eBGP neighbor to establish a peering session using the real autonomous-system number (from the local BGP routing process) or by using the autonomous-system number configured with the ip-address argument (local-as)
R5(config-router)#neighbor 15.1.1.1 local-as 500 no-prepend replace-as
DUAL-AS
The dual-as keyword is used to configure the eBGP neighbor to establish a peering session using the real autonomous-system number (from the local BGP routing process) or by using the autonomous-system number configured with the ip-address argument (local-as)
alo
ReplyDelete