topic ASA 5505 Blocking Webex in Network Security

ASA 5505 Blocking Webex

patrick.hurley — Sun, 03 May 2020 23:18:49 GMT

I don’t have any issues when I bypass my ASA firewall and use my U-verse WiFi to connect to Webex. When I look at the log when trying to connect to Webex, I see a bunch of icmp packets being blocked. Has anyone seen this issue with Webex?

Re: ASA 5505 Blocking Webex

Sheraz.Salim — Mon, 04 May 2020 01:10:07 GMT

Can you share your logs and firewall configuration.

Re: ASA 5505 Blocking Webex

Scott Leport — Mon, 04 May 2020 19:09:43 GMT

Check you've got these ports setup on your ASA, although a copy of the logs and configuration would help.

https://help.webex.com/en-us/WBX000028782/Network-Requirements-for-Webex-Teams-Services

Alternatively, use the ASDM logging monitor to verify what ports are being negotiated during your WebEx session and apply to your ASA appropriately.

Re: ASA 5505 Blocking Webex

patrick.hurley — Mon, 04 May 2020 20:26:20 GMT

I think I found the issue. For whatever reason, Webex sends a rapid number of ICMP packets and it does like a DOS attack so my firewall drops the packets. I whitelisted the subnet.