A dual-stack connection can reach IPv6 sites but IPv4-only destinations fail. The most expensive fix is rarely the best first experiment. Reproduce the exact failed task before changing settings.
What the user actually sees
Primary symptom. A dual-stack connection can reach IPv6 sites but IPv4-only destinations fail. Record the precise point of failure and whether the same input, account or connected device succeeds in another supported mode. That working comparison establishes the scope of the repair.
Separate configuration from service faults
The first hypothesis is a mismatch in the failing path. Compare IPv4 address, gateway and DNS resolution separately from IPv6. The second is a lower-level state that the interface may not show: trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. A third possibility is a feature or version limitation, which should be checked against supported documentation before a reset.
For this Network issue, capture adapter, gateway, route, DNS and access point telemetry and compare the same traffic from a second trusted device and a controlled network route. Preserve the last known working configuration so you can tell whether a successful retry came from an actual correction or a temporary recovery.
Read the evidence
| What you observe | What it suggests | Focused response |
|---|---|---|
| A dual-stack connection can reach IPv6 sites but IPv4-only destinations fail | The failure affects the specific workflow described here; the entire system is not necessarily broken. | Compare IPv4 address, gateway and DNS resolution separately from IPv6. |
| The basic comparison exposes a difference between a working and failing configuration. | A local setting, version, account context or device route deserves attention. | Correct the missing IPv4 route, lease or WAN provisioning rather than disabling IPv6. |
| The same failure persists after a reversible correction. | A deeper dependency or compatibility issue may remain. | Trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. |
Before changing anything: Do not expose the host by adding permissive firewall rules. Save a screenshot or anonymized log line, record the previous setting, and back up relevant user data. Do not reset every related service just because one test fails.
Choose a recovery route. The Beginner path checks compare IPv4 address, gateway and DNS resolution separately from IPv6. The Advanced path investigates trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. They address different evidence; use the path that matches your result.
Step-by-Step Troubleshooting
Choose the Beginner route for reversible checks or Advanced for evidence-driven diagnosis.
Check the affected device or service
A dual-stack connection can reach IPv6 sites but IPv4-only destinations fail. Before editing settings, note the exact time, affected account or device, and whether it started after an update, move, hardware change or network change. This is the baseline for the IPv6 Websites Work but IPv4 Connections Time Out guide.
Check iPv4 address, gateway and DNS resolution separately from
Compare IPv4 address, gateway and DNS resolution separately from IPv6. Observe whether the symptom changes. A clean comparison tells you which part of the process is healthy and avoids unnecessary resets.
Adjust the missing IPv4 route, lease or WAN provisioning rather
Correct the missing IPv4 route, lease or WAN provisioning rather than disabling IPv6. Change only this variable, record its former value, and try the failing action once. If there is no improvement, restore the prior configuration before exploring the Advanced route.
Verify an IPv4-only test site and a dual-stack site both load
An IPv4-only test site and a dual-stack site both load normally. Repeat using the same account, network, file, title or hardware condition that previously failed. Do not count a different test as confirmation.
Inspect supporting logs
Collect the error text or state relevant to IPv6 Websites Work but IPv4 Connections Time Out. Record adapter, gateway, route, DNS and access point telemetry; anonymize account IDs, public IPs and secret-bearing log fragments before sharing.
Inspect iPv4 NAT and default-gateway forwarding while checking
Trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. Record the difference between successful and failed cases and keep the first meaningful error rather than the last cascade message.
Rule out related configuration drift
Where practical, compare the same traffic from a second trusted device and a controlled network route. If the alternate case works, return to the single configuration difference instead of changing multiple services. Use the vendor-supported method for your current version.
Verify and record results
An IPv4-only test site and a dual-stack site both load normally. Leave the previous value documented for rollback, then monitor one normal operating cycle. If symptoms recur, attach the sanitized evidence to a vendor or administrator support request.
What not to assume
After the first corrective action, interpret the result carefully. If the original task now works, leave the other settings unchanged. If it still fails, trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. Compare the same traffic from a second trusted device and a controlled network route rather than adding random fixes on top of one another.
For escalation, retain adapter, gateway, route, DNS and access point telemetry, the original output, and a single before/after comparison. Redact passwords, tokens and personal data. A support agent can then distinguish the same traffic from a second trusted device and a controlled network route from a general outage without repeating risky actions.
Verification procedure
Pass condition: An IPv4-only test site and a dual-stack site both load normally. The validation must exercise the same path that failed originally. A successful settings screen, single ping, application homepage or idle system is not enough if the original failure appears during a different action.
Repeat the test under the original conditions once after a safe relaunch, reconnect or new session. For intermittent failures, record the time and the difference between a clean result and a failed one instead of claiming success from a single attempt.
Prevention and next steps
If the problem persists, restore any test-only settings, preserve the evidence and stop before destructive reset, firmware flash or credential recreation. Give official support the exact symptom, the first failing timestamp and what the comparison established. Do not expose the host by adding permissive firewall rules.
Prevent recurrence: Document the working correction: Correct the missing IPv4 route, lease or WAN provisioning rather than disabling IPv6. Retain the accepted result (an IPv4-only test site and a dual-stack site both load normally) as a future regression test after configuration, software or hardware changes.
Solution Checklist
Questions specific to this fault
How do I know the symptom is actually resolved?
An IPv4-only test site and a dual-stack site both load normally. A generic diagnostic test outside the affected workflow is not a substitute.
Should I reset or reinstall everything first?
No. Compare IPv4 address, gateway and DNS resolution separately from IPv6. Then choose the smallest supported intervention: correct the missing IPv4 route, lease or WAN provisioning rather than disabling IPv6. Preserve recoverable settings and user data.
What should I include in a support request?
Provide the exact failing action, product and version, time, non-sensitive log evidence, and this deeper observation: Trace IPv4 NAT and default-gateway forwarding while checking DHCP lease state. Do not include credentials or private customer data.
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