# Intermittent External Network Connectivity Issues Affecting Build VMs

- Provider: [Harness](https://down.guide/harness)
- Level: confirmed
- Impact: Degraded
- lasted 21h 24m
- started 2026-07-30 05:59 UTC
- Continuous Integration Enterprise(CIE) - Linux Cloud Builds, Continuous Integration Enterprise(CIE) - Linux Cloud Builds, Continuous Integration Enterprise(CIE) - Linux Cloud Builds +2
- us, us-central1, us-west1
- id: DWN-403f9c4969
- Official page: https://stspg.io/qdjcv8bw5w5x

## Updates from Harness
### 2026-07-30 05:59 UTC: investigating
Summary - We are intermittently facing network connectivity issues with our Build VM's unable to connect to external resources.
We are currently investigating the issue.

### 2026-07-30 08:07 UTC: monitoring
A fix has been implemented and we are monitoring the results.

### 2026-07-30 08:07 UTC: monitoring
We are continuing to monitor for any further issues.

### 2026-07-31 03:22 UTC: resolved
This incident has been resolved.

### 2026-08-07 19:32 UTC: postmortem
## Summary
CI runners in the us-west1 and us-central1 regions intermittently experienced connection timeouts of approximately 134 seconds when reaching external services such as GitHub and Bitbucket over outbound network gateways.
## Impact
\* CI runners in the affected regions intermittently experienced connection timeouts of approximately 134 seconds when reaching external services \\(e.g., GitHub, Bitbucket\\) over our outbound network gateways.
\* The issue was intermittent rather than constant — connections succeeded under normal load, and failures clustered during periods of high outbound traffic volume.
\* No data was lost or corrupted. This was a network-connectivity and capacity issue, not a data-integrity issue.
\* us-west1 and us-central1 were the affected regions; other regions were not impacted by this issue.
## Root Cause
‌
Our load balancer distributes outbound traffic across multiple NAT gateways using a hashing method based on connection details \\(source/destination address and port\\). For any single connection, these details stay constant for that connection's lifetime. We had a sustainted traffic surge for a few seconds which congested the gateways
‌
## Action Items
To prevent such issues from happening again Harness will,
Increase outbound connection capacity on our NAT gateways by provisioning additional external network interfaces, giving each gateway a substantially larger pool of connections it can serve concurrently..

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