How to set up Application Gateway WAF custom rule on Application Gateway

By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30

Why this matters

Set up application gateway waf custom rule on a Application Gateway device is one of the highest-volume how-to searches for the Azure Enterprise category. Most users find the menu path inconsistent across Application Gateway model revisions, so this guide gives a generalised path plus model-specific notes.

Pre-requisites

• A Application Gateway device that's powered on and on the latest stable service version / OS.
• The Application Gateway companion app or management tool installed and signed in.
• 5-15 minutes uninterrupted.

Step-by-step

1. Locate the setting. Open settings on your Application Gateway device. For "set up Application Gateway WAF custom rule", the option lives under one of: General, Advanced, Connectivity, Accessibility, or a Application Gateway-specific menu. Check the Application Gateway user manual for your exact model if you can't find it.
2. Toggle the feature on. Confirm the on-screen prompt.
3. Configure sub-options. Most features have 2-3 sub-options (mode, schedule, paired device). Pick values that match your real-world usage pattern.
4. Save / apply. Some Application Gateway models auto-save, others require an explicit Done / Save tap.
5. Test live. Trigger the feature in a real scenario to confirm the configuration is correct.

Tips that save time

• Pair this feature with a Application Gateway automation / routine if the device supports it.
• If the feature relies on cloud sync, give it 1-2 minutes after enabling to propagate.
• For multi-user households / multi-admin teams, set per-user profiles so each user sees their preferred state.

Common gotchas

• Feature greyed out. usually service version too old. Update + retry.
• Feature works once then stops, battery saver / power saver mode is killing the Application Gateway app process. Whitelist it.
• Feature works but with delay: usually cloud-sync latency; check internet speed and Application Gateway service status.

Region / variant notes

Some Application Gateway features are region-locked or only available on higher-tier SKUs. If your variant doesn't show "set up Application Gateway WAF custom rule" at all, check the Application Gateway model spec sheet to confirm support.

Frequently asked questions

How long should the recovery / setup take?

For most Application Gateway Azure Enterprise cases, allow 15-45 minutes the first time. Repeats are usually under 10 minutes once you know the menu path.

Will this exact procedure work on every Application Gateway model?

The procedure reflects current Application Gateway behaviour. Menu paths shift between service version generations; verify against the manual for your specific model + revision.

Is the procedure safe in production / live use?

Apply during a maintenance window where possible. Capture pre-change state. Application Gateway doesn't usually publish rollback procedures, so make sure you can restore manually.

Does this affect my Application Gateway support coverage?

Standard operation per the user manual + applying official service version updates does NOT void support coverage. Opening managed services, third-party repair, or unauthorised modifications can void support coverage, check before going further.

Related guides

• All Azure Enterprise guides → /microsoft/section/azure_enterprise.html
• All Microsoft guides → /microsoft/

Related fixes

Related guides worth a look while you sort this one out:

• How to set up Application Gateway WAF custom rule on AKS
• How to set up Application Gateway WAF custom rule on Azure AI Search
• How to set up Application Gateway WAF custom rule on Azure Arc
• How to set up Application Gateway WAF custom rule on Azure Backup
• How to set up Application Gateway WAF custom rule on Azure Firewall
• How to set up Application Gateway WAF custom rule on Azure OpenAI

References

• Application Gateway official support portal for your model.
• Application Gateway community forum + Reddit threads.
• Vendor PSIRT / advisory page (where applicable).

Reference material, not professional advice. Validate with your vendor manual and follow local regulations.

Why this matters for your day-to-day

the affected device that's misbehaving costs more than the fix itself: lost productivity, missed calls, security risk, even safety risk in some categories. Treating the symptom quickly with a documented procedure is cheaper than letting it persist. The steps above are written to get you back to working in under an hour where possible, and to flag clearly when escalation is the right call.

Before you start

A few things to confirm so the hardware fix goes cleanly:

• Latest service version downloaded if you're going to update.
• support coverage + support contract status checked. opening managed parts may void it.
• Backup of current configuration (where applicable) taken.
• Spare parts on hand if you anticipate replacement.
• Adequate workspace, lighting, and time, rushing causes regressions.

Verification checklist

After applying the fix on your unit, confirm:

• The original symptom is no longer reproducible.
• Related features (status service health indicators, app sync, paired accessories) still work.
• The device responds to a soft reboot without the fault returning.
• Any error codes that were on display have cleared.
• Documentation (your service log, the brand companion app) reflects the change.

Escalation guide

For the affected device, the right escalation depends on impact:

• Cosmetic / minor: log a ticket via the How app or web portal. Response 1-3 business days.
• Mid-impact: phone support. Have your serial number ready.
• Critical (production down, safety issue): in-person dealer / TAC visit. Bring proof of purchase.
• Out of support coverage: third-party repair shop with manufacturer-certified technicians.

More frequently asked questions

Is it safe to apply during business hours?

If the device is in production use, apply during a scheduled maintenance window. Most procedures need 2-15 minutes of downtime. Capture pre-change state so you can roll back if needed.

Can I roll this back if something breaks?

Yes for software-level changes (service version rollback, config rollback). Hardware changes are usually one-way. Always back up settings before starting.

Are there safer alternatives for non-technical users?

Yes: the manufacturer's self-service troubleshooter (HP Smart, LG ThinQ, Samsung Members, similar) usually walks through the same steps in a guided UI. Use that first if you're not comfortable with menu paths.

Does this affect other devices on my network?

Generally no. The procedure is local to this device. Network-side changes (service version updates that affect TLS, SMB, or routing) are flagged explicitly in the steps.

Will the procedure work on the international variant?

Some features and service version paths are region-locked. Check the model spec sheet to confirm your variant supports the menu option referenced. If you're outside the US/EU, look for the regional support portal.

Field notes from real Azure Enterprise incidents

When I work on set up Application Gateway WAF custom rule on Application Gateway the rhythm I lean on is the one I have built over years of these tickets, not a stack of generic advice. When a customer says 'Azure broke', the answer is almost always either RBAC propagation lag or a quota that quietly tightened on a region they did not check. Network Watcher's connectivity check has saved me from blaming Azure when the problem turned out to be a stale NSG rule someone left behind from a pilot.

I have lost more hours to Azure Resource Graph queries than I would like to admit, but the alternative, clicking through the portal hoping the right blade loads. is worse. Activity Log is the first place I open on any Azure regression because the operation that flipped the state is usually right there at the top of the list.

Tools I actually reach for

For set up Application Gateway WAF custom rule on Application Gateway on Application Gateway the cheapest signal I can land usually comes from Network Watcher, then Azure Advisor, az aks get-credentials when Network Watcher cannot see the layer the fault sits in, and Azure Portal Resource Explorer for the cases where neither of those answers cleanly. That ordering is not academic. It matches the layers the failure tends to surface through, so the cheap signal lands first and the heavier tooling only comes out when the simpler answer does not hold up under scrutiny.

Verification I run before I close the ticket

Before I mark set up Application Gateway WAF custom rule on Application Gateway resolved on a Application Gateway unit, the verification loop below is what I actually run. Each step proves a different layer is green, and the order matters - the cheap checks gate the more expensive ones.

az aks browse --resource-group RG --name CLUSTER  # verify dashboard reachable

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

az monitor activity-log list --resource-group RG --max-events 25 -o table

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

az network watcher test-connectivity --source-resource VM1 --dest-resource VM2

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

az resource list --resource-group RG --query "[].{name:name,type:type}" -o table

If that one comes back clean, move to the next check. If it does not, stop and dig in there before layering more verification on top of a red signal.

az account show --query '{sub:id,tenant:tenantId}' -o table

Only when every line above runs clean do I close the ticket and update the runbook with the timestamps.

Where I check first when the docs disagree

When two sources contradict each other on a Azure Enterprise detail, the disambiguation order I lean on is stable. I usually start at learn.microsoft.com/azure for the ground-truth view on Azure Enterprise. I usually start at techcommunity.microsoft.com for the ground-truth view on Azure Enterprise. I usually start at azurecharts.com for the ground-truth view on Azure Enterprise. I usually start at azure.microsoft.com/updates for the ground-truth view on Azure Enterprise. Random blog posts and reseller wikis are signal, not ground truth, and I treat them as such until the references above either confirm or contradict the claim.

Pitfalls I have walked into on this exact path

The shortcuts that look smart on set up Application Gateway WAF custom rule on Application Gateway have a habit of biting back. The pitfalls below are the ones I have personally walked into on a Application Gateway unit, not things I read about. Network Watcher's connectivity check has saved me from blaming Azure when the problem turned out to be a stale NSG rule someone left behind from a pilot. When a customer says 'Azure broke', the answer is almost always either RBAC propagation lag or a quota that quietly tightened on a region they did not check. When in doubt I revert to the slower path that the manual prescribes - the time I save by skipping it is always smaller than the time I spend cleaning up afterwards.

What I tell the next on-call

When I hand set up Application Gateway WAF custom rule on Application Gateway off to the next person on rotation, the three lines I leave in the runbook are these. First, the symptom signature for Application Gateway on the Azure Enterprise family - not a paraphrase, the exact string that surfaces. Second, the diagnostic that gave the highest signal in the least time. Third, the exact verification command whose green output justified closing the ticket. That trio is what turns a one-off fix into a runbook entry the next engineer can use without paging me at three in the morning.

I also add a one-line note on the cost of getting this wrong. For set up Application Gateway WAF custom rule on Application Gateway on a Application Gateway unit, the cost is rarely the replacement part. It is the downtime, the second site visit, and the trust deficit you spend with whoever owns the asset when the fix does not hold. That framing keeps the next on-call from choosing the cheap-looking shortcut that ends up costing the most in elapsed hours and goodwill.