Hello everyone. I believe everything I call up on the internet is being seen by others. I was told by somebody that my ISP, Comcast, doesn't really provide any hardware firewall protection, despite what they may say. He told me to get a hardware firewall box/device that just plugs into my current modem/router. Can anyone recommend a specific product model? (BTW, if it matters, I don't use wifi and usually only use one device at a time, but sometimes I use two computers at same time.) Thanks.
Where do they say that? You did not tell us anything about your computer but Windows includes a very capable firewall. Even a very basic router provides a significant layer of protection, including firewall type protection. So, IMO, you don't need to buy anything else. You say you don't use wifi. That suggests you connect to your gateway device (the modem/router) via Ethernet. That's great as the easiest way for a bad guy to hack into your network (that's just network, not your computers) is via wifi. That said, if you did not do it already, I recommend you enter your modem/router's admin menu and change the passphrase and admin passwords. Never let them stay at the defaults. What are you using for security software? I use Windows Defender as it is very capable and already included in Windows 8.1 and Windows 10. If using W7, Microsoft Security Essentials is plenty good. And again, Windows (all versions back to XP) have a capable firewall built in. It is very unlikely anybody can see what you are doing unless you purposely granted someone remote access. If you are "click-happy" on unsolicited downloads, attachments, links and popups, your computers could become compromised - especially if you don't keep Windows updated. But even then, a decent and fully updated anti-malware solution should yell at you telling you something suspicious is happening. In addition to whatever security you are using, I recommend Malwarebytes Free as a supplemental scanner just to make sure your primary scanner (or you) did not let something malicious slip by. So far, since I started using Windows Defender when Windows 8.x came out, nothing as got by on any of my 6 systems here. And if you like Malwarebytes, it does run great in real-time along side other anti-malware solutions, including Windows Defender.
What @Bill_Bright says about firewalls etc. Your ISP can see what websites you visit. For sites that don't use HTTPS, it can also see what pages you browse, and all of the content that you receive and send. With HTTPS, it only sees hostnames (like "www.wilderssecurity.com") but not full URLs (like "www.wilderssecurity.com/threads/i-think-everything-i-see-on-my-monitor-is-being-seen-by-others.394632/"). And it can't see the content either. If you care about that, you can use a VPN service. But then the VPN provider can see the same stuff that the ISP could. So you pick a VPN service that you trust more than your ISP.
Fortunately, most sites use HTTPS these days. That means even if your ISP wanted to see it, they couldn't. They could see data going back and forth, but it would be encrypted. Since you live in the US, I would not worry that your ISP is watching, or about using a VPN unless you are conducting illegal activities on your computer. I will assume you are not. Understand most of the major ISPs in this county have 10s of millions subscribers with many of those having multiple users/computers at each address. For example, I have 6 connected computers, a connected smart TV, connected Roku streamer, a connected smart DVR, and two connected Blu-Ray players that are often used to stream Netflix. All these devices are connected through one IP address. So even with a court order, it would be an expensive and time consuming ordeal to actually see what I am doing. ISPs just don't have the resources to monitor your activities even if they wanted too. Plus, they know there are watchdog groups out there making sure such monitoring is not happening without some court order. Now, as far as a nosy neighbor or a bad guy parked out in front of your house, that's another story IF they had access to your network. But since you use Ethernet and have hopefully changed the default wifi passphrase, and hopefully keep Windows updated and use a decent antimalware solution, I would not even worry about them. That leaves avoiding being "click happy" as described above, or somebody you know coming into your home and sitting down at your computer. And hopefully you can control that too.
