peer connect-interface
Use peer connect-interface to specify a source interface (IPv4 address/IPv6 address) for establishing TCP connections to a peer or peer group.
Use undo peer connect-interface to remove the configuration.
Syntax
peer { group-name | ipv6-address [ prefix-length ] } connect-interface interface-type interface-number
undo peer { group-name | ipv6-address [ prefix-length ] } connect-interface
Default
BGP uses the primary IPv4 or IPv6 address of the output interface in the optimal route destined for the BGP peer or peer group as the source address.
Views
BGP instance view
BGP-VPN instance view
Predefined user roles
network-admin
Parameters
group-name: Specifies a peer group by its name, a case-sensitive string of 1 to 47 characters. The peer group must have been created.
ipv4-address: Specifies a peer by its IPv4 address. The peer must have been created.
mask-length: Specifies a mask length in the range of 0 to 32. You can use the ipv4-address and mask-length arguments together to specify a subnet. If you specify a subnet, this command specifies a source interface for establishing TCP connections to all dynamic peers in the network.
ipv6-address: Specifies a peer by its IPv6 address. The peer must have been created.
prefix-length: Specifies a prefix length in the range of 0 to 128. You can use the ipv6-address and prefix-length arguments together to specify a subnet. If you specify a subnet, this command specifies a source interface for establishing TCP connections to all dynamic peers in the subnet.
interface-type interface-number: Specifies an interface by its type and number.
Usage guidelines
The peer connect-interface command and the peer source-address command can both change the source address for establishing TCP connections. If you execute both commands, the most recent configuration takes effect.
The peer source-address and peer connect-interface commands are applicable to the following scenarios:
The peer's IPv4/IPv6 address does not belong to the interface directly connected to the local router. To ensure successful TCP connection establishment, use one of the following methods:
Specify the interface to which the IPv4/IPv6 address belongs as the source interface on the peer.
Specify the IPv4/IPv6 address of the interface directly connected to the local router as the source address on the peer.
On a BGP router that has multiple links to a peer, the source interface for TCP connection changes because the primary source interface fails. To avoid this problem, specify a loopback interface as the source interface or specify the IP address of a loopback interface as the source address.
You want to establish multiple BGP sessions to a router. In this case, BGP might fail to determine the source address for each TCP connection based on the optimal route to the peer. To prevent this problem, use one of the following methods:
If the BGP sessions use IP addresses of different interfaces, specify a source interface or source address for each session.
If the BGP sessions use different IP addresses of the same interface, specify a source address for each session.
The source interfaces on the local router and the peer must be reachable to each other.
After you configure this command, BGP immediately tears down the session to a directly connected IBGP peer when the source interface (non-loopback interface) fails and the link state goes down.
To specify an indirectly connected interface on an EBGP peer as the source interface, use the peer ebgp-max-hop command. The command allows the establishment of an EBGP session to the indirectly connected peer.
If an interface has multiple IPv4 addresses, BGP uses the primary IPv4 address to establish TCP connections. If an interface has multiple IPv6 addresses, BGP selects a source IPv6 address. To use an IPv6 address as the source address, specify that IPv6 address by using the peer source-address command.
You cannot specify a virtual template (VT) interface as the source interface for establishing TCP connections because a VT interface cannot process services.
Examples
# In BGP instance view, specify loopback 0 as the source interface for TCP connections to peer group test.
<Sysname> system-view [Sysname] bgp 100 [Sysname-bgp-default] peer test connect-interface loopback 0
Related commands
peer ebgp-max-hop
peer source-address