https://www.barracuda.com/products/network-protection/web-security-gateway
Barracuda Web Security Gateway lets organizations benefit from online applications and tools without exposure to web-borne malware and viruses, lost user productivity, and misused bandwidth.
https://documentation.meraki.com/MX/Content_Filtering_and_Threat_Protection/Content_Filtering
Meraki is a Cisco Conent Filtering product that allows you to block certain websites based on your organizational policies.
https://www.cde.state.co.us/dataprivacyandsecurity/networkfirewallpolicy
This sample document serves as an example network firewall implementation policy to help protect internal networks and manage traffic in and out of the network.
https://www.currentware.com/blog/web-content-filtering/
Web content filtering is critical for protecting networks and users against web-based threats, objectionable internet content, and distracting website. This is a potential solution provided by CurrentWave
https://www.dhs.gov/sites/default/files/publications/privacy-pia-nppd-einstein3a-may2016.pdf
Web Content Filtering (WCF) provides protection at the application layer for web traffic by blocking access to suspicious websites, preventing malware from running on systems and networks, and detecting and blocking phishing attempts as well as malicious web content.
https://expertinsights.com/insights/the-top-dns-web-filtering-platforms-for-businesses/
A list of web content filtering solutions provided by Expert Insights.
https://learn.microsoft.com/en-us/previous-versions/tn-archive/cc700820(v=technet.10)
This article covers the design, deployment, and use of both network and host-based firewalls.
https://learn.microsoft.com/en-us/previous-versions/tn-archive/cc700828(v=technet.10)
This module helps you to select a suitable firewall product for your organization's perimeter network.
https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-41r1.pdf
This NIST Special Publication provides information to organizations about firewall technologies and policies.
https://csrc.nist.gov/projects/cprt/catalog#/cprt/framework/version/SP_800_53_5_1_0/home?element=SC-7
NIST resource that defines the requirements for boundary protection.