Losing the Internet connection

Situation: One of network computers lost the Internet connection. The computer can still access to all network resources but the Internet. It can’t ping the Cisco ASA firewall and any public IP addresses. The ASA can’t ping the host. This is the contention: Internet—ASA—Switch—SonicWall—Switch—Host.

The SonicWal and the host can ping each other. SonicWall can see host arp table but ASA can’t.

Flush the host arp table on SonicWall fixes the problem.

 

 

Published by

Bob Lin

Bob Lin, Chicagotech-MVP, MCSE & CNE Data recovery, Windows OS Recovery, Networking, and Computer Troubleshooting on http://www.ChicagoTech.net How to Install and Configure Windows, VMware, Virtualization and Cisco on http://www.HowToNetworking.com

One thought on “Losing the Internet connection”

  1. I bet your SonicWall is stopping your ASA from seeing the ARP.

    At the end of the day “I think” its your SonicWall causing the issue and not your firewall.

    Remember your SonicWall is running your IPS (blocking traffic) and your ASA is only a firewall, its allowing or denying traffic, but its not going to switch back and forward/allowing and denying.

    If the SonicWall is doing its job, its blocking traffic from an infected PC. Check your SonicWALL logs or clean the infected computer.

    -James

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