OpenAI API / OpenAI API

OpenAI SDK Non-Streaming Calls Hang Indefinitely Behind NAT Due to Missing TCP Keepalive

Fix indefinite hanging on long OpenAI API calls caused by NAT gateway idle timeout dropping TCP connections without keepalive Includes evidence for OpenAI API troubleshooting demand.

Source-backed Last updated May 20, 2026 1 source Needs local verification

Category: OpenAI API
Error signature: Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive
Quick fix: Compare the failing environment with a known working setup, then change one configuration value at a time.
Updated: May 20, 2026
Verification status: Source-backed
Evidence: 1 public source URL

Before you change production

This page includes public source URLs in the imported troubleshooting record. Compare those references with your version and environment before applying changes.

Reproduce the smallest failing action and save non-secret logs before changing configuration.
Check versions for OpenAI API, related SDKs, package managers, CI runners, and hosting providers.
Change one setting or dependency at a time, then rerun the same failing command or request.
Avoid destructive commands, credential rotation, billing changes, or security relaxations without a rollback plan.

What this error means

Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive is a OpenAI API failure pattern reported for developers trying to fix indefinite hanging on long openai api calls caused by nat gateway idle timeout dropping tcp connections without keepalive. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Open issue #3269 on openai/openai-python (created May 19, 2026, labeled 'bug'). The default httpx transport has SO_KEEPALIVE off. During long non-streaming calls, NAT gateways silently drop idle TCP connections while server generates response — user never receives it. Affected: Responses API with reasoning models and completions.create(). This is a production-breaking bug affecting paying users with enterprise infra.

Common causes

Open issue #3269 on openai/openai-python (created May 19, 2026, labeled 'bug'). The default httpx transport has SO_KEEPALIVE off. During long non-streaming calls, NAT gateways silently drop idle TCP connections while server generates response — user never receives it. Affected: Responses API with reasoning models and completions.create(). This is a production-breaking bug affecting paying users with enterprise infra.

Quick fixes

Confirm the exact error signature matches Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive.
Check the OpenAI API account, local tool state, and provider configuration involved in the failing workflow.
Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

Verify the command, editor, extension, or API client that produced the error.
Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

Capture the exact error message and the command, editor action, or request that triggered it.
Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
Review the source evidence below and compare it with your environment.
Apply one change at a time and rerun the smallest failing action.
Keep the working fix documented for the team or deployment environment.

How to prevent it

Keep provider/tool configuration documented.
Record non-secret diagnostics such as tool version, provider name, model name, and command path.
Add a lightweight check before CI or production workflows depend on the tool.

Diagnostic flow for this page

Match Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive exactly before applying the quick fix.
Compare the failing environment with OpenAI API versions, account scope, provider settings, and deployment context.
Check the listed common causes in order, starting with the cause that best matches your logs.
Use the evidence status below to decide whether to confirm against public sources or official documentation.
Apply one reversible change, rerun the smallest failing action, and keep rollback notes.

FAQ

What does Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive mean in OpenAI API?

Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive indicates the workflow described by "OpenAI SDK Non-Streaming Calls Hang Indefinitely Behind NAT Due to Missing TCP Keepalive" failed in a OpenAI API context. Start by confirming the exact signature and the component that emitted it.

What should I check first for Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive?

Check whether this cause matches your environment: Open issue #3269 on openai/openai-python (created May 19, 2026, labeled 'bug'). The default httpx transport has SO_KEEPALIVE off. During long non-streaming calls, NAT gateways silently drop idle TCP connections while server generates response — user never receives it. Affected: Responses API with reasoning models and completions.create(). This is a production-breaking bug affecting paying users with enterprise infra.

Is the Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive guidance source-backed?

The "OpenAI SDK Non-Streaming Calls Hang Indefinitely Behind NAT Due to Missing TCP Keepalive" page is labeled source-backed. It has 1 public source URL from github.com, so use that evidence status when deciding how much additional verification you need.

When should I avoid the quick fix for Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive?

For "OpenAI SDK Non-Streaming Calls Hang Indefinitely Behind NAT Due to Missing TCP Keepalive", avoid applying "Compare the failing environment with a known working setup, then change one configuration value at a time." when the error text differs, the affected version or provider is different, or the change would touch credentials, billing, DNS, production deploy settings, or irreversible data.

What should I collect before debugging Non-streaming OpenAI API calls silently hang forever behind NAT — default httpx transport has no TCP keepalive?

For "OpenAI SDK Non-Streaming Calls Hang Indefinitely Behind NAT Due to Missing TCP Keepalive", collect the failing OpenAI API command or request, non-secret configuration, versions, timestamps, request IDs when available, and the smallest reproduction that still triggers the signature.