Cannot access Zoom Website or App while in office

[zionzz]

Hi, my office cannot access any zoom relate app or website. Only show ERR_CONNECTION_RESET in Chrome.

In app it show error code:1005456000

But when connect to another network, everything works.

We checked zoom ip and port list here

https://support.zoom.com/hc/en/article?id=zm_kb&sysparm_article=KB0060548#h_01EJHWFBNWZ34RMGW03S65RV...

But all I see in firewall outbound are using port 137 which is not listed in required port. So, it all deny.

Example below are outbound IP and port that firewall deny during testing.

Some are Zoom IP with wrong port but I'm not sure about others.

40.126.53.24:137

51.141.119.73:137

52.109.89.119:137

52.109.44.112:137

52.184.217.56:137

170.114.52.2:137 

152.195.38.76:137

23.11.200.26:443

23.11.200.138:443

172.217.194.94:443

142.251.12.147:443

Please tell me what to check further. 

[Candlshep]

Hi I have the same exact problem! Did you happen to figure it out? Thanks

[jrmagno]

Possible Causes and Steps to Check:

1. Incorrect Firewall Configuration:

   • The outbound connections on port 137 being blocked in your firewall logs suggest that your network might have some misconfigured rules.
   • Port 137 is used for NetBIOS Name Service (NBNS), which is unrelated to Zoom. These logs might indicate a network misconfiguration or an unrelated service that’s being mistakenly blocked or flagged.

   • Required Ports and IP Ranges for Zoom:

     Firewall or Network Security Device Blocking Zoom Traffic:

     • If your firewall or a network security device (like a proxy or IDS/IPS) is blocking or interfering with traffic to Zoom servers, it may need adjustments or exceptions.
     • Check that Zoom IP ranges are whitelisted correctly on all relevant security devices. Sometimes, firewalls block requests based on deep packet inspection, application rules, or geolocation restrictions.

     • DNS or Routing Issues:

       • Verify that DNS is correctly resolving Zoom domains. Sometimes, DNS resolution issues can lead to ERR_CONNECTION_RESET errors.
       • Check for any misconfigurations or DNS filtering that could block or redirect Zoom traffic.

       • Check for Other Network Restrictions:

         • Ensure there are no bandwidth restrictions, proxies, or VPNs that might interfere with Zoom traffic.
         • Ensure network throttling or Quality of Service (QoS) policies aren’t deprioritizing Zoom traffic.

Zoom network firewall or proxy server settings

If your app stays in a "connecting" mode or has timed out due to Network error, please try again or Can't connect to our service, please check your network connection and try again issues, it could be related to your network connection, network firewall settings, or web security gateway settings.

Zoom requires specific ports and IP ranges to be allowed through the firewall for its services to function properly. Ports 443/TCP and 8801-8810/TCP are commonly used for Zoom meetings.

[Candlshep]

Thank you, but would you be able to talk me through this?