Is it a Virus?
✔ NO - Safe
Located in C:\Windows\System32\arp.exe
Warning
Typically light resource usage; unusual activity or location outside System32 may indicate a concern
arp.exe is OS-provided; verify location and signature if anomalies appear
Can I Disable?
✔ NO
arp.exe is integral to local network address resolution; disabling can disrupt connectivity. Use network configuration to limit use if needed.
What is arp.exe?
arp.exe is the Windows Address Resolution Protocol (ARP) utility that maintains the local ARP cache by mapping IP addresses to MAC addresses on a local network. It runs within the OS networking stack to support efficient packet delivery and is typically located in System32. The tool is invoked automatically by network services and commands when address resolution is required.
arp.exe interacts with the ARP table by issuing requests and processing replies to bind IPv4 addresses to hardware addresses. It updates and protects the cache, supports gratuitous ARP, and cooperates with the IP stack to ensure local network traffic can reach the correct devices.
Quick Fact: Windows uses ARP to accelerate local traffic; arp.exe is invoked by the OS when needed and does not remain in the foreground.
ARP Roles
- ARP Cache Manager: Maintains the local ARP cache for Windows networking.
- Network Neighbor Resolver: Assists in resolving IP addresses to MAC addresses during communication.
- Diagnostics Helper: Used by network tools to query or flush ARP entries.
- Security Boundary: Participates in legitimate ARP traffic to support safe local networking.
- System Integrator: Interacts with the IP stack and device drivers to ensure address resolution works correctly.
Is arp.exe Safe?
Yes, arp.exe is safe when it is the legitimate Windows ARP tool located in C:\Windows\System32\arp.exe and signed by Microsoft.
Is arp.exe a Virus or Malware?
The real arp.exe is NOT a virus. Malware sometimes uses similar names to masquerade as legitimate utilities.
How to Tell if arp.exe is Legitimate or Malware
- File Location: Must be in
C:\Windows\System32\arp.exe. Any arp.exe elsewhere is suspicious.
- Digital Signature: Right-click the file in File Explorer > Properties > Digital Signatures. Should show a signature from
Microsoft or Microsoft Windows Publisher.
- Resource Usage: Normal arp.exe usage is minimal CPU; unusually high usage or persistent activity outside network events is suspicious.
- Behavior: arp.exe should be invoked by the OS for address resolution. Constant ARP operations started by other processes may indicate spoofing.
Red Flags: If arp.exe is located in unusual folders (like Temp or AppData), runs when there is no network activity, lacks a valid signature, or spawns unusual network requests, run a malware scan. Look for copies in paths such as C:\Users\<user>\AppData\Local\Temp\arp.exe or C:\Program Files\arp.exe.
Why Is arp.exe Running on My PC?
arp.exe runs when Windows requires ARP resolution for local network communication or when network diagnostics requests access the ARP cache. It may appear briefly during normal operation or when a network service queries the ARP table.
Reasons it's running:
- Active Local Network Communication: When the OS talks to devices on the same LAN, ARP entries are created or refreshed to map IPs to MAC addresses.
- Background Network Services: System services that monitor or manage networking may invoke ARP queries or cache maintenance in the background.
- Network Diagnostics or Troubleshooting: Commands like ipconfig, ping, or netsh can trigger ARP resolution to verify reachability.
- ARP Cache Maintenance: Windows periodically refreshes or prunes the ARP cache to keep mappings current.
- Startup or NIC State Changes: On boot or after NIC changes, ARP lookups occur to re-establish local neighbor mappings.
Can I Disable or Remove arp.exe?
No, arp.exe should not be removed. It is a core OS networking component. You can flush ARP cache or limit ARP traffic via network configuration, but removing arp.exe is not recommended.
How to Stop arp.exe
- Do not terminate arp.exe manually: arp.exe is a system utility that may run on demand; do not end it unless instructed by support.
- Flush ARP cache: Open an elevated Command Prompt and run: <code>arp -d *</code> to clear the cache.
- Disable ARP-related activity on a NIC: Open Network Connections, right-click the active adapter, Properties, and adjust IPv4 settings to minimize ARP reliance.
- Restart networking: Restart the machine or disable/enable the network adapter to reinitialize ARP state.
- Monitor with safety checks: If ARP behavior seems abnormal, run malware scans and verify signatures for arp.exe in C:\Windows\System32.
How to Uninstall arp.exe
- ✔ arp.exe is a built-in Windows utility and cannot be uninstalled without modifying core OS files; consider performing a Windows Repair if you suspect corruption.
- ✔ If you suspect a compromised system, run DISM /Online /Cleanup-Image /RestoreHealth and SFC /SCANNOW from an elevated prompt.
- ✔ As an alternative, you can disable or restrict ARP-related functionality at the network adapter level or use third-party network tools for monitoring.
Common Problems: ARP-Related Issues
If arp.exe or ARP-related networking behaves oddly, the following common problems and solutions can help diagnose and restore proper LAN address resolution.
Common Causes & Solutions
- Stale ARP Entries: Clear the ARP cache and re-establish mappings: run arp -d * in an elevated prompt.
- ARP Cache Poisoning Suspected: Ensure the network is secure; verify devices on the LAN and consider enabling security features on managed switches; run malware scans.
- ARP Requests on Unknown Devices: Investigate new devices on the network; ensure firewall rules allow only authorized devices; monitor ARP traffic with network tools.
- ARP Cache Size or Expiry Issues: Restart the NIC or reboot the machine to refresh ARP state; review NIC driver settings for ARP stability.
- Misconfigured IPv4 Settings: Check IP configuration, subnet mask, and gateway; fix misconfigurations that cause unnecessary ARP activity.
- Outdated Network Drivers: Update NIC drivers to latest version; verify that the ARP behavior aligns with driver capabilities.
Quick Fixes:
1. Open an elevated Command Prompt and run arp -a to inspect current ARP entries.
2. Clear ARP cache: arp -d *
3. Restart the network adapter: disable and re-enable the NIC in Network Connections
4. Update NIC drivers from the manufacturer or Windows Update
5. Run a malware scan to rule out malicious ARP-related activity
Frequently Asked Questions
Is arp.exe safe to run on Windows?
Yes. arp.exe is the built-in Windows ARP utility located in C:\Windows\System32\arp.exe and is signed by Microsoft. Only if it appears in a nonstandard location or without a valid signature should you investigate.
Where is arp.exe located on a typical system?
C:\Windows\System32\arp.exe is the standard location; copies outside System32 or in user folders can be suspicious and warrant scanning.
How do I flush the ARP cache?
Open an elevated command prompt and run: arp -d * to delete all ARP cache entries, then allow Windows to repopulate as needed.
Can I disable arp.exe permanently?
Not recommended. arp.exe is used by the OS for local network address resolution. You can limit ARP activity per NIC, but do not remove the executable.
Why is arp.exe running when I have no network activity?
ARP resolution can occur during normal system tasks, or due to background services and startup networking. If you notice persistent activity, verify with Task Manager and scan for malware.