Specifying Peers That Are Not Directly Connected; Table 13: Source Addresses And Default Next Hop Addresses For Various Configurations - Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual

Table 13: Source Addresses and Default Next Hop Addresses for Various Configurations

Configured Neighbor Configured Update
Address Source Address
IPv4 neighbor address IPv4 source address
IPv4 neighbor address IPv6 source address
IPv4 neighbor address Interface name
IPv6 neighbor address IPv6 source address
IPv6 neighbor address IPv4 source address
IPv6 neighbor address Interface name
You can override a native IPv6 next-hop address with either the neighbor
update-source command or an outbound route map.
When you specify an interface with the neighbor update-source command, the
IPv4-mapped IPv6 address of the interface is used instead of the native IPv6 address
for the next hop.
In this example, the IPv4-mapped IPv6 address of the loopback 0 interface is the
next-hop address sent when IPv6 prefixes are advertised. However, if loopback 0
has an IPv6 address, then that address is used as the default next hop for advertising
IPv6 prefixes.

Specifying Peers That Are Not Directly Connected

Normally, EBGP speakers are directly connected. When you cannot connect EBGP
speakers directly, you can use the neighbor ebgp-multihop command to specify
that the neighbor is more than one hop away. You generally need static routes to
Source Address used
for TCPv4 and TCPv6
Connection
IPv4 source address
Not allowed
IPv4 address of the
interface. If the
interface does not have
an IPv4 address, then
the session does not
come up.
IPv6 source address
Not allowed
IPv6 address of the
interface. If the
interface does not have
an IPv6 address, then
the session does not
come up.
host1(config)#interface loopback 0
host1(config-if)#ip address 10.1.1.1/32
host1(config-if)#exit
host1(config)#router bgp 100
host1(config-router)#neighbor 2::2 update-source loopback 0
Chapter 1: Configuring BGP Routing
Default Next Hop Default Next Hop
Value for IPv4 Prefixes Value for IPv6 Prefixes
IPv4 source address IPv4 source address
mapped to an IPv6
address
Not allowed Not allowed
IPv4 address of the IPv6 address of the
interface interface. If the
interface does not have
an IPv6 address, then
the IPv4 address of the
interface is mapped to
an IPv6 address.
0.0.0.0 IPv6 source address
Not allowed Not allowed
IPv4 address of the IPv6 address of the
interface. If the interface
interface does not have
an IPv4 address, then
0.0.0.0.
Configuring BGP Peer Groups
31