In the 90s and early 2000s, before broadband took over, ISPs offered dial-up access through thousands of local phone numbers. Hackers and phreakers quickly realized these numbers could be exploited. By war-dialing exchanges and identifying modem handshakes, they could find valid ISP numbers, brute-force login credentials, and gain free internet access. Some would spoof caller ID or trick authentication systems into thinking they were paying customers. Entire lists of “free ISP dialups” circulated underground forums and BBSes, allowing global access through someone else’s phone bill or corporate lines.

This method was eventually curbed as ISPs upgraded authentication, moved to centralized radius servers, and broadband made dial-in obsolete. But for a brief time, exploiting dial-in access was a gateway to the early internet.

#Phreaking #DialupDays #HackTheNet #OldSchoolHacking #InternetHistory #BBS #ISPHacks