Bitcoin clients connect to other bitcoin nodes on TCP port 8333 by default. Some Bitcoin users have reported issues attempting to connect or receive connections to their bitcoin clients across port 8333, according to a latest report by CCN.
After spending an entire day in vain trying to open 8333, one ATT U-verse (a bundled package similar to others offered by well-known Cable Companies/ISPs) customer approached customer support.
“After hours of phone calls and messaging ATT finally told me the truth of what was going on, and only because I noticed it myself and demanded an answer. The internet is being routed through a DVR/cable box, and they confirmed the DVR also has a firewall.”
The problem arises when the ISP has complete control over the hardware from the user’s house to their router to the Internet. Many well-known providers will deliberately close a number of connection ports to facilitate what they believe to be the optimum level of service.
“Perhaps this is the driving force behind the inexplicable and massive decline in Bitcoin nodes. Bitcoin is being censored by the ISPs themselves, and they won’t even tell you that. I had to get in touch with headquarters and threaten to rip it out of the wall to