BGP neighbor establish

======================BGP establish neighbor eBGP===========

conditions : establish TCP seison

1- eBGP multihop

note :  + modify value TTL

+ establish for eBGP per neighbor

command : router bgp {as}

neighbor a.b.c.d ebgp-multihop {TTL value}

+ minimum TTL = 0 ( with minimum TTL value = 0,it can establish neighbor )

2- Disable-Connected-Check

note :  + no check TTL feild

+ only apply for 2 router link connected

command : router bgp {as}

neighbor a.b.c.d disable-connected-check

3- ttl-security

note :  + establish for eBGP per neighbor

+ increase hop value {255-hop value}

 if TTL > = TTL local - >>>> neighboor is establish

If TTL < TTL local - >>>> Drop and no icmp.

+ thuong ap dung chinh sach trong iBGP

command : router bgp {as}

neighbor a.b.c.d ttl-security hops {0-255}