Redis UI Unreachable After Disabling IPv6 Capabilities on Node OS – Redis Knowledge Base

After IPv6 capabilities are disabled at the operating system level, the Redis Enterprise Envoy service may fail to start the Redis UI on port 8443.
This issue occurs when Redis Enterprise is still configured to use IPv6, while the underlying OS no longer supports it.

This article outlines the key symptoms and log messages, explains why the Redis UI becomes unreachable when IPv6 is disabled at the OS level, and provides step-by-step instructions to restore access and verify the fix.

Quick Fix Table

Symptom	Fast Check	Resolution
Redis UI unreachable after OS updates	Run `rlcheck` → reports connectivity failure on port 8443	Disable IPv6 in Redis Enterprise using `rladmin cluster config ipv6 disabled`
Envoy running but port 8443 closed	Check `envoy.log` for `malformed IP address: ::` errors	Confirms IPv6 disabled at OS level but still enabled in Redis Enterprise
UI accessible only after revert	Re-enable IPv6 in OS and Redis Enterprise	Use `rladmin cluster config ipv6 enabled`

Symptoms

When IPv6 is disabled at the OS level but not within Redis Enterprise, you may observe:

Redis UI becomes unreachable (often after OS or security hardening updates).
Port 8443 not listening: the envoy process fails to bind the UI port.
Misleading process status: supervisorctl status envoy shows RUNNING, but the UI remains inaccessible.

Connectivity check failures:

Stopping on Error: connectivity check failed from 10.10.10.21 to localhost for the following ports: 8443

Envoy log entries:
```
malformed IP address: ::
```

Root Cause

The Redis Enterprise Envoy proxy requires IPv6 support unless it is explicitly disabled within the cluster configuration.
If IPv6 is turned off at the OS level without doing so in Redis Enterprise, the Envoy process cannot open port 8443, leading to UI inaccessibility.

Resolution

To restore access to the Redis UI:

SSH into any node in the Redis Enterprise cluster.
Disable IPv6 support in Redis Enterprise: rladmin cluster config ipv6 disabled
Allow a few moments for the Envoy service to reload.
Confirm that the Redis UI on port 8443 is now reachable.

Verification

After applying the fix:

Run rlcheck again — connectivity check should complete with no port 8443 failures.
Confirm the Redis UI loads successfully in your browser.
Review /var/opt/redislabs/log/envoy.log — malformed IPv6 address errors should no longer appear.

Optional: Re-enable IPv6

If IPv6 is later restored on the host OS, you can re-enable it within Redis Enterprise using:

rladmin cluster config ipv6 enabled

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