OCI Networking guide: Inconsistent Connectivity Between Compute Instances in Different Subnets
I'm deploying to production and I'm building a feature where I've searched everywhere and can't find a clear answer..... I'm working with a question with instances in Oracle Cloud Infrastructure (OCI) where compute instances located in different subnets need to communicate with each other reliably. Both instances are in the same Virtual Cloud Network (VCN) and security lists allow all traffic, yet I intermittently receive timeouts when trying to ping or SSH into the other instance. Here are the details: I have two compute instances, `InstanceA` and `InstanceB`. `InstanceA` is in `Subnet1` (CIDR 10.0.1.0/24) and `InstanceB` is in `Subnet2` (CIDR 10.0.2.0/24). The route table for the VCN has a local route that should allow traffic between these subnets. My security list for both subnets looks like this: ```plaintext Ingress Rules: - Source CIDR: 10.0.0.0/16, IP Protocol: All, Source Port Range: All, Destination Port Range: All Egress Rules: - Destination CIDR: 10.0.0.0/16, IP Protocol: All, Source Port Range: All, Destination Port Range: All ``` I've checked the Network Security Group (NSG) rules, and they seem to be configured correctly as well. To test connectivity, I tried pinging `InstanceB` from `InstanceA`: ```bash ping 10.0.2.x # Replace with InstanceB's private IP ``` Interestingly, it works about 50% of the time. When it fails, I get a timeout behavior, and I also notice that SSH attempts unexpected result intermittently with a 'Connection timed out' message. I tried using TCP dumps on both instances to trace the packets, but I don’t see any incoming packets arriving at `InstanceB` from `InstanceA` during the failures. I also verified that both instances have proper public and private IP addresses assigned and that the OCI service health dashboards report no issues. Has anyone else experienced similar issues with OCI subnets? What could be causing this inconsistent connectivity? Any tips for troubleshooting or configuration changes to ensure reliable communication would be appreciated! This is part of a larger API I'm building. This is my first time working with Bash 3.10. I'm working in a CentOS environment. What's the correct way to implement this? This issue appeared after updating to Bash LTS. I'm working on a CLI tool that needs to handle this. Could someone point me to the right documentation?