HPE Aruba router: ARP poisoning / spoofing detected
By Sai Kiran Pandrala · reviewed by Sai Kiran Pandrala, Editor Last verified: 2026-05-30
| Vendor | HPE Aruba |
|---|---|
| Operating system | ArubaOS-CX |
| Category | IP / Network Issue |
| Skill level | Intermediate to advanced |
| DIY-able? | Yes with CLI access; some scenarios need Aruba TAC + RMA. |
What this guide covers
Fix ARP poisoning / spoofing detected on a HPE Aruba router.
Step-by-step
- Identify the offending source MAC via debug or capture.
- Enable DHCP snooping + Dynamic ARP Inspection on access VLANs.
- Mark uplinks as trusted; untrusted ports rate-limit + validate.
- Monitor inspection statistics for repeat attacks.
CLI / commands
show interface brief
show interface 1/1/1
show system
When the issue persists
- Open a Aruba TAC case with the tech-support bundle.
- Provide the timeline + recent changes.
Frequently asked questions
Will this work on my specific ArubaOS-CX version?
The procedure reflects current ArubaOS-CX behaviour. Older releases may need minor syntax adjustments, use the CLI help (? or tab-completion) to verify.
Should I open a Aruba TAC case immediately?
Open one if you suspect hardware failure or the symptom persists after a maintenance-window reload. Make sure your support entitlement is active first.
Where can I find the HPE Aruba official documentation?
https://community.arubanetworks.com/. search the product family + feature name.
Is this procedure safe in production?
Test in a lab or maintenance window first. Capture pre-change state so you can roll back.
Related guides
Related fixes
Related guides worth a look while you sort this one out:
- HPE Aruba firewall: ARP poisoning / spoofing detected
- HPE Aruba switch: ARP poisoning / spoofing detected
- HPE Aruba router: asymmetric routing detected
- HPE Aruba router: duplicate IP address detected
- Best HPE Aruba router for branch office
- Best HPE Aruba router for enterprise data centre
References
- HPE Aruba support portal: https://www.arubanetworks.com/support-services/
- HPE Aruba knowledge base: https://community.arubanetworks.com/
- HPE Aruba security advisories: https://www.arubanetworks.com/support-services/security-bulletins/
- Open a case: https://asp.arubanetworks.com/
Reference material, not professional advice. Validate against your specific ArubaOS-CX version and test in a non-production environment before applying.
Why this matters for your day-to-day
A HPE 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 HPE device fix goes cleanly:
- Latest firmware downloaded if you're going to update.
- Warranty + support contract status checked, opening sealed 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 HPE device, confirm:
- The original symptom is no longer reproducible.
- Related features (status LEDs, 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 a HPE device, the right escalation depends on impact:
- Cosmetic / minor: log a ticket via the HPE 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 warranty: third-party repair shop with manufacturer-certified technicians.
More frequently asked questions
Does this affect other devices on my network?
Generally no. The procedure is local to this device. Network-side changes (firmware updates that affect TLS, SMB, or routing) are flagged explicitly in the steps.
What if the fix returns after a reboot?
Persistent fault returns mean either: a hardware fault (escalate), a configuration that's being overwritten by a sync source (check cloud profiles), or a regression in a recent firmware update (rollback).
Can I roll this back if something breaks?
Yes for software-level changes (firmware 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.
How often should I run preventive checks?
Quarterly for most consumer devices; monthly for production / commercial devices. Set a calendar reminder so the device stays healthy between issues.
Topology deep dive
Before you touch a single command, picture where this CX switch / gateway sits. In most of the BFSI rollouts I have run, the branch box hangs off a dual-uplink design: one circuit from Airtel and a backup from BSNL or a Reliance Jio enterprise leased line. The CX switch / gateway terminates both, then hands traffic up to a core pair sitting in the NSE colo at BKC or a private data centre in Mumbai or Hyderabad. If you do not know which uplink is primary, you will chase ghosts.
The control plane matters here. CX switch / gateway units phone home to Central for policy, licensing, and config push. When Central loses sight of a device the symptom often looks like a local hardware fault when it is really an overlay or reachability problem. So my first split is always: is this box physically sick, or has it just gone dark to the controller? Five minutes of console time settles that question.
Underneath, the L2 fabric is plain spanning-tree or MSTP with a handful of VLANs: one for the corporate LAN, one for guest, one for management, sometimes a PCI-DSS-scoped segment for card data. A BFSI auditor will ask you to prove that the cardholder VLAN never leaks into guest. Keep that map in your head, because half the routing and ARP weirdness you will ever debug traces back to a VLAN that ended up in the wrong trunk allow-list.
Configuration walkthrough
I keep a known-good baseline for every CX switch / gateway model so I am never reconstructing config from memory at 2am. The walkthrough below is the order I touch things, not a copy-paste dump. On ArubaOS-CX the context model is strict, so you drop into the right block, change one thing, and verify before moving on.
# Enter config, confirm you are on the device you think you are
configure terminal
hostname BLR-BRANCH-01
# Management reachability to the controller first - nothing else matters if this is down
interface mgmt
ip static 10.20.0.11/24
default-gateway 10.20.0.1
exit
# VLAN + trunk baseline (the allow-list is where most outages hide)
vlan 10
name CORP-LAN
vlan 20
name GUEST
vlan 99
name MGMT
interface 1/1/1
description UPLINK-AIRTEL-PRIMARY
vlan trunk allowed 10,20,99
exit
Notice I name the uplink with the carrier baked in. When a Reliance circuit flaps at 3am, the on-call engineer in the SOC sees UPLINK-AIRTEL-PRIMARY versus UPLINK-RJIL-BACKUP in the interface description and knows instantly which provider to call. That naming convention has saved me a dozen escalations. Commit only after you have eyeballed the diff.
Troubleshooting commands by platform
Different HPE Aruba families speak slightly different dialects. ArubaOS-CX uses the modern show tree; older Comware-based ProVision and Comware 7 boxes (the 5900/5950 series you still find in legacy NSE/BSE colo racks) use display. Know which one you are on before you type.
ArubaOS-CX
show version
show environment power
show environment fan
show environment temperature
show module
show interface brief
show events -d
diag dump core
Comware (HPE FlexNetwork / legacy core)
display version
display power
display fan
display device
display interface brief
display logbuffer
display diagnostic-information
The mapping is mechanical: show environment power on CX equals display power on Comware. If you support a mixed estate (and most BFSI shops do, because procurement buys in waves), tape that mapping to the inside of your laptop lid. I did, for two years.
India compliance and deployment notes
Hardware in a regulated Indian network is never just a box on a rack. If this CX switch / gateway carries cardholder or PII traffic, you are inside RBI cyber-security framework scope and the new DPDP Act data-handling rules. That changes how you handle a faulty unit: you cannot simply courier a dead box back to HPE with config and logs intact. Wipe it. erase all zeroize on CX, or pull and physically destroy the storage if the chassis will not boot enough to wipe.
Procurement runs through GeM (Government e-Marketplace) for any PSU or central-government tender, and through Redington or Ingram Micro as the usual HPE distributors for private enterprise. A spare branch-class unit lands around INR 1.6L to INR 3.2L depending on port count and PoE budget; a chassis PSU spare is INR 18,000 to INR 45,000. SmartNet-equivalent HPE Foundation Care or Pointnext renewals run INR 85,000 to INR 2L per year for a branch stack, more for a core pair with 4-hour onsite.
CERT-In matters too. If the hardware fault turns out to be the visible end of a security event - say a port died because someone fried it during a tamper attempt - you have a six-hour incident-reporting clock to CERT-In. Log everything with timestamps in IST. Auditors love a clean timeline and hate "around midnight".
A real-world deployment I did
During a BSE colo migration a CX switch / gateway started reporting MAC flaps between two ports. Turned out a contractor had cross-patched a loop while dressing cables. STP should have caught it but the loop was on an edge port with portfast/admin-edge on. We enabled loop-protect, killed the offending patch, and the flap storm stopped. Layer-2 loops in a trading colo are not academic; milliseconds cost money there.
The wider point: document the box, the circuit, and the controller relationship in one place your night-shift engineer can read cold. The fault you are debugging tonight is rarely exotic. It is usually a thing you already knew about a different site, written down somewhere you forgot to look.
More frequently asked questions, extended
How do I tell a controller-reachability problem from a real hardware fault?
Console straight into the CX switch / gateway. If the box boots clean and show environment is green but Central still shows it offline, the hardware is fine and you have an overlay or WAN reachability problem. If the console itself is dead or POST fails, it is hardware. The console is the source of truth; the controller dashboard is a convenience.
Can I run mixed firmware across a branch fleet?
Briefly, during a staged rollout, yes. As a steady state, no. Central policy push assumes a tight version band, and mixed code invites feature-parity bugs. Pick a target train, canary it, roll the fleet, then close the gap. I never let a fleet sit on more than two adjacent releases.
What logs should I grab before I call HPE Aruba TAC?
On ArubaOS-CX: show tech redirected to a file, plus show events and the output of show environment. On Comware: display diagnostic-information. Attach the serial and entitlement ID. A TAC engineer who gets a clean tech-support bundle on the first message closes the case days faster than one who has to ask for it.
Is it safe to do this during NSE/BSE trading hours?
For anything in the trading path, no. Schedule it for the post-close window after 15:30 IST or the weekend maintenance slot. Capture pre-change state so you can roll back inside the window. A 90-second blip during continuous trading is a reportable event you do not want your name on.