Pods in RKE cluster unable to access external IP addesses

I have a single node RKE cluster with a very simple setup - see below. It starts ok, and everything internally seems to work ok. However, none of the pods can access any ip addresses external to the cluster. I’m fairly new to this, but I don’t think this is the expected behavior. For example, CoreDNS doesn’t work for external addresses because it can’t get the the external DNS server on our network. Any suggestions as to what is causing this and how to fix it? Here is my cluster.yml:

cluster_name: miketest
nodes:
  - address: mtest5
    user: test
    role: [controlplane, etcd, worker]
services:
  etcd:
    snapshot: true
    creation: 6h
    retention: 24h
# Required for external TLS termination with ingress-nginx v0.22+
ingress:
  provider: nginx
  options:
    use-forwarded-headers: "true"