1. In case of explicit proxy forwarding to Cloud SWG using on-prem Proxy device, if the auto selected data center location via proxy.threatpulse.net is not providing the nearest / desired Cloud SWG data center location, you can use on-prem Proxy configuration to selectively send traffic to your preferred location.
2. Also this is helpful in case the auto selected location by proxy.threatpulse.net is not providing desired performance, you will have the ability to control within the on-prem Proxy device to failover to a different Cloud SWG data center location.
This is only applicable when using on-prem Proxy device to explicitly forwarding traffic towards Cloud SWG.
The general guidance to setup on-prem explicit proxy forwarding to Cloud SWG can be found in this article. Along with the complete setup guide this provide the steps for setting up forwarding host on the on-prem ProxySG and CPL policies for forwarding traffic to Cloud SWG. You can use the same guidance but instead of creating one set of forwarding host , you have to create 3 sets of forwarding host for 3 different data center location. All the different data center's location name and forwarding host VIP name can be found under KB 208150.
For example if your on-prem Proxy devices are located in Toronto, we can use the nearest data center VIP gcato2-vip1.threatpulse.net as primary location. As a secondary location we can use Montreal data center VIP gcamo1-vip1.threatpulse.net. And as a tertiary location you can relay on the default Cloud SWG host name proxy.threatpulse.net. With these three sets of forwarding host, on-prem ProxySG's forwarding host configuration should look like below
; Unintercepted SSL
url.scheme=(ssl, tcp) forward(PrimaryWSSHTTP8080, SecondaryWSSHTTP8080, TertiaryWSSHTTP8080)
; Intercepted SSL
url.scheme=https forward(PrimaryWSSInterceptedHTTPS8084, SecondaryWSSInterceptedHTTPS8084, TertiaryWSSInterceptedHTTPS8084)
; Plaintext HTTP
url.scheme=http forward(PrimaryWSSSecure8443, SecondaryWSSSecure8443, TertiaryWSSSecure8443)
Having the 3 failover hosts in a sequence will provide below advantages
1. On-prem ProxySG by default performs TCP based health check. If on-prem proxy observes Primary forwarding hosts are failing it will automatically switch over to secondary and tertiary group. also will automatically go back to Primary groups when health check is recovered.
2. This provides customers with a better control on their side for situation where customer's data center IP is not connecting to the closest Cloud SWG data center location using proxy.threatpulse.net.
3. Also this provided customer a control to manually failover to a different data center, incase if there is degraded performance observed on the primary datacenter location. Proxy admin can execute following commands or script them from management center as well to failover to secondary data center
disable sick fwd.PrimaryWSSSecure8443
disable sick fwd.PrimaryWSSHTTP8080
disable sick fwd.PrimaryWSSInterceptedHTTPS8084
This is make the on-prem ProxySG to consider primary forward hosts group is no longer healthy and it will automatically start sending traffic to secondary groups based the configured CPL policy. This does not drop (on interrupt user's live session) the existing connections that were already established with primary groups. Only new connections that are made on the on-prem ProxySG will be forwarded to the secondary group.
Also This change can be done from the web UI of the on-prem ProxySG. From configuration --> health check --> edit all the Primary forwarding hosts and disable the health check as unhealthy like below
To revert back to the primary group again, proxy admin can enable the health check on primary group using below CLI commands. Also can be scripted via management center
Incase of manual failover to the tertiary group, both primary and secondary groups failover has to be marked as "unhealthy / sick". Tertiary failover will always go back to the default global Geo load balancing logic provided by Broadcom to select the most optimized Cloud SWG data center location.