Enable Next-hop Recursion for BGP4

Access global configuration mode.
```
device# configure terminal
```
Access BGP configuration mode.
```
device(config)# router bgp
```
Access address-family IPv4 unicast configuration mode.
```
device(config-bgp-router)# address-family ipv4 unicast
```

Enable recursive next-hop lookups.

device(config-bgp-ipv4u)# next-hop-recursion