Use this command to configure BGP to use a specific IP address as the source address for the TCP connection with a neighbor. This IP address must be the IP address configured on the peer as its neighbor address for this router.
The IP address used as the source address in IP packets sent to a neighbor must be the same address used to configure the local system as a neighbor of the neighbor router. In other words, if the update source is configured, it must be the same IP address used in the neighbor remote-as command on the peer.
It is common to use an IP address on a loopback interface because a loopback interface is always reachable, as long as any routing interface is up. The peering session can stay up as long as the loopback interface remains reachable. If you use an IP address on a routing interface, then the peering session will go down if that routing interface goes down.
Issue this command in Peer Template Configuration Mode to add it to a peer template.
| Default | When no update source is configured, TCP connections use the primary IPv4 address on the outgoing interface to the neighbor. |
| Format | neighbor {ipv4-address | autodetect interface interface-name } update-source interface |
| Mode |
|
| Parameter | Description |
|---|---|
| ipv4-addressIipv6- address | The neighbor's IPv4 or IPv6 address. This is the IP address on the link that connects the two peers. If the neighbor's IPv6 address is a link local address, the local interface must also be specified. |
| auto-detect interface interface-name | The neighbor's IPv6 link local address that will be auto detected on the specified interface. |
| update-source interface | The primary IPv4 address on this interface is used as the source IP address for the TCP connection with the neighbor. |
