Comcast DNS server keeps me from connecting to the internet elsewhere

Dan Bryant1 wrote:

Hmm, I do occasionally use PureVPN, so I will experiment with that to see if it is part of the equation. But if uninstalling it is the solution, then what's the point of having VPN?

There is no point in having a VPN if you are not using it to create a private tunnel to a corporate or similar private network. If you are using a VPN your DNS will be overwritten to that provided by the VPN server

Dan Bryant1 wrote:

I have a MacBook Pro running Catalina. At my office I have CenturyLink and I have Comcast at home. The last 2 days when I came into the office I could not connect to the internet on our wifi network. I talked to the CenturyLink tech and they told me to set my DNS to 205.176.3.65 which I did. Went home and did a few things on the internet but didn't touch my settings. Today when I came back in to the office, I couldn't connect and discovered the DNS was set back to 75.75.75.75 (for Comcast). So why does this happen on some days and not others? Is there a way to make it automatically set to the right DNS or am I going to have to keep doing this manually?

BTW, I remember the day when I first discovered this a few years back. I was on a road trip and frustrated that I could connect t to the internet in some locations but not others. I was sitting in a coffee shop trying to figure out why I couldn't connect when everyone else could. I just started playing with the advanced settings in network preferences, not really knowing what they did, and discovered that when I deleted the DNS server, which was also set to 75.75.75.75,, everything suddenly worked. And I thought, how come I had never heard of this? I am usually the most tech savvy guy in the office and somehow had never known about this trick. So far every time I haven't been able to connect, my DNS was set to Comcast's server and I wasn't on a Comcast network, so maybe this is unique to Comcast users?

Comcast likes to route your through their DNS.

You do not make it clear if you are carrying your Notebook computer between locations...

You can try Renew your IP address from the DHCP server on Mac - Apple ...

Manually change your DNS, some examples:

Google DNS

Preferred: 8.8.8.8

Alternate: 8.8.4.4

OpenDNS

Preferred: 208.67.222.222

Alternate: 208.67.220.220

Specify a DNS server on Mac - Apple Support

Uninstall any third party antivirus, VPN, Cleaners or optimizers is always recommended.

Using DHCP, it should get DNS settings from the router. The router address will show up in the list gray.

If you add an address, it should show up in black.

I don't know how Comcast could change the DNS server without you having installed some Comcast software onto your Mac.

Unless your VPN is connected to your organization at the other end you are exposing your financial data to more insecurity. Public VPN servers get access to all your data then they reroute that data to the Internet just as you would have if you did not use a VPN. The owners of the Public VPN servers then can sell your data. Public VPN servers do not have some kind of special connection to your banking institution, retail stores, etc.

If you use HTTPS when connecting to web sites your data is encrypted.

Set your dns servers to public dns like 8.8.8.8 and 8.8.4.4. These are provided by Google. There are several others.