Connection to MySQL (AWS RDS) in Istio
The protocol in your EgressRule definition should be tcp. The service should contain the IP address or a range of IP addresses in CIDR notation.
Alternatively, you can use the --includeIPRanges flag of istioctl kube-inject, to specify which IP ranges are handled by Istio. Istio will not interfere with the the not-included IP addresses and will just allow the traffic to pass thru.
References: