We are currently sending our guest wifi traffic over Cisco Umbrella. This accounts for a huge swath of our overall traffic, as our locations are in shopping malls and other retail centers, so people will connect and use the guest wifi when nearby. We are implementing a splash page and lowering the DHCP lease time for the guest wifi, but I still foresee this being a problem.
Has anyone had any issues with sending only specific VLANs over Cisco Umbrella and dumping the rest directly to the internet? I understand we'd lose the additional security and visibility of Umbrella for this network, but it's already a bunch of noise we can't do much about. We're looking at blacklisting any malware or otherwise compromised devices from our guest wifi, but that's going to take time to develop.