local-address (Protocols BGP)
Syntax
local-address address;
Hierarchy Level
[edit logical-systems logical-system-name protocols bgp], [edit logical-systems logical-system-name protocols bgp group group-name], [edit logical-systems logical-system-name protocols bgp group group-name neighbor address], [edit logical-systems logical-system-name routing-instances routing-instance-name protocols bgp], [edit logical-systems logical-system-name routing-instances routing-instance-name protocols bgp group group-name], [edit logical-systems logical-system-name routing-instances routing-instance-name protocols bgp group group-name neighbor address], [edit protocols bgp], [edit protocols bgp group group-name], [edit protocols bgp group group-name neighbor address], [edit routing-instances routing-instance-name protocols bgp], [edit routing-instances routing-instance-name protocols bgp group group-name], [edit routing-instances routing-instance-name protocols bgp group group-name neighbor address]
Description
Specify the address of the local end of a BGP session. This address is used to accept incoming connections to the peer and to establish connections to the remote peer. When none of the operational interfaces are configured with the specified local address, a session with a BGP peer is placed in the idle state.
You generally configure a local address to explicitly configure the system’s IP address from BGP’s point of view. This IP address can be either an IPv6 or IPv4 address. Typically, an IP address is assigned to a loopback interface, and that IP address is configured here.
For internal BGP (IBGP) peering sessions, generally the loopback interface (lo0) is used to establish connections between the IBGP peers. The loopback interface is always up as long as the device is operating. If there is a route to the loopback address, the IBGP peering session stays up. If a physical interface address is used instead and that interface goes up and down, the IBGP peering session also goes up and down. Thus, the loopback interface provides fault tolerance in case the physical interface or the link goes down, if the device has link redundancy.
When a device peers with a remote device’s loopback interface
address, the local device expects BGP update messages to come from
(be sourced by) the remote device’s loopback interface address.
The local-address statement enables you to specify the
source information in BGP update messages. If you omit the local-address statement, the expected source of BGP update messages is based on
the device’s source address selection rules, which normally
result in the egress interface address being the expected source of
update messages. When this happens, the peering session is not established
because a mismatch exists between the expected source address (the
egress interface of the peer) and the actual source (the loopback
interface of the peer). To ensure that the expected source address
matches the actual source address, specify the loopback interface
address in the local-address statement.
Although a BGP session can be established when only one
of the paired routing devices has local-address configured,
we strongly recommend that you configure local-address on
both paired routing devices for IBGP and multihop EBGP sessions. The local-address statement ensures that deterministic fixed addresses
are used for the BGP session end-points.
If you include the default-address-selection statement
in the configuration, the software chooses the system default address
as the source for most locally generated IP packets. For protocols
in which the local address is unconstrained by the protocol specification,
for example IBGP and multihop EBGP, if you do not configure a specific
local address when configuring the protocol, the local address is
chosen using the same methods as other locally generated IP packets.
Default
If you do not configure a local address, BGP uses the routing device’s source address selection rules to set the local address.
Options
address—IPv6 or IPv4 address of the local end of the connection.
Required Privilege Level
routing—To view this statement in the configuration.
routing-control—To add this statement to the configuration.
Release Information
Statement introduced before Junos OS Release 7.4.