Failed to Send RIP Update Packets to Neighbors

A device cannot send RIP Update packets to neighbors when the link runs properly.

Run the display current-configuration configuration rip command to check RIP configurations.
- Check whether RIP has been enabled on the interface. Only the RIP-enabled interface can send RIP packets.
- Check whether the silent-interface command has been executed on the interface. If the command has been executed, the interface does not send RIP packets.
Run the display current-configuration interface interface-type interface-number command to view the interface configuration.
- Check whether the undo rip output command has been executed on the interface. If the command has been executed, the interface does not send RIP packets.
- Check whether the authentication modes on the two ends of the link are the same. If the authentication modes are different, the interface cannot send RIP packets to the peer.
- Check whether split horizon has been enabled on the interface. If split horizon has been enabled, the interface cannot send the route learned by itself to neighbors.
  
  Split horizon is enabled on all interfaces by default, but the display current-configuration command output does not show the split horizon option. If the command output for an interface connected to an NBMA network does not contain the split horizon option, split horizon is disabled on the interface.