A user is unable to browse any web pages.

Since the user can ping 8.8.4.4 (an external IP address) but is unable to browse web pages, it indicates that the DNS (Domain Name System) settings may be incorrect or not configured. The DNS system is crucial for translating human-friendly domain names into IP addresses. If DNS settings are incorrect, the browser cannot resolve domain names, thus web pages will not load despite the network itself being reachable via IP. The other options are less likely as they would affect connectivity to external IP addresses or the availability of specific websites.