aws network_error ai_generated true

Could not connect to Neptune endpoint: Connection timed out

ID: aws/aws-neptune-connection

Also available as: JSON · Markdown
83%Fix Rate
85%Confidence
40Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
2 active — — —

Root Cause

Client cannot connect to Neptune graph database due to VPC networking, security groups, or IAM auth issues.

generic

Workarounds

  1. 88% success Ensure client is in the same VPC and security group allows port 8182 
    Check security group allows inbound TCP on port 8182 from the client's security group or CIDR

    Sources: https://docs.aws.amazon.com/neptune/latest/userguide/security-vpc.html

  2. 82% success Use an EC2 instance or Lambda in the same VPC as a jump host for external access 
    SSH tunnel: ssh -L 8182:NEPTUNE_ENDPOINT:8182 ec2-user@BASTION_IP

    Sources: https://docs.aws.amazon.com/neptune/latest/userguide/get-started-connecting.html

Dead Ends

Common approaches that don't work:

  1. Try to connect to Neptune from outside the VPC 95% fail

    Neptune is VPC-only with no public endpoint; external access requires SSH tunneling or a VPN

  2. Change Neptune instance class to fix connection issues 90% fail

    Instance class affects performance, not network connectivity

Error Chain

Leads to: