Websense from 2005, BlueCoat evaluated against IronPort and migrated floor by floor, OpenDNS, McAfee Web Gateway — which later became SkyHigh — and finally Palo Alto. Each migration overlapped the one before it rather than replacing it cleanly. Capacity was the recurring constraint rather than policy: the gateways ran to processor exhaustion under load and were answered by standing up four more.
The two-tier split
City staff traffic on the corporate gateway, public library terminals on a separate service, migrated branch by branch with the subnets enumerated in each change order.
A government workplace and a public library sitting on the same infrastructure have genuinely incompatible obligations. One is an employer setting acceptable use for its own staff. The other is a public accommodation where blocking carries First Amendment exposure and the tolerance for over-filtering is close to zero. Running both under one policy would have been wrong in both directions, so the split was the architecture rather than a configuration detail.
The governance instrument
The ITD Web Filter Change Form, carried through seven revisions and bound explicitly to the City’s published Internet and Web Use Policy, so that an unblock request was a documented and signed decision against a standard rather than an administrator’s discretion.
This matters more in government than it would elsewhere. Filtering decisions and filtering reports are public records, and they were in fact requested as such. The form existed so that every answer had a policy behind it and a name on it.
The last platform decision, scored on a fourteen-year-old sheet
The final platform choice was made on 17 May 2023 using the quadrant workbook created on 18 March 2009 — the same file that had decided the 2009 security platform selection, scored twelve systems for application security risk in 2012, ranked fourteen enterprise resource planning modules in 2013 and chosen a firewall in 2019.
Five platform generations of web filtering across eighteen years, and the instrument that ended it was older than three of them.
Outcome
Two incompatible obligations served correctly by one estate, with every filtering decision documented against a published policy.