That's what my ISP does. What's worse is that sometimes their dns servers fail intermittently (something to do with fragmented packets and retrying DNS queries in TCP mode).
It did take a while to figure out what was causing the intermittent DNS failures. "My ISP is hijacking all port 53 traffic" was fairly low on my list of possibilities, I must admit.
Fortunately it's not that hard to run a local resolver that forwards queries to an external resolver on a vps on an alternate port.
I'd switch ISPs, but I live in a remote area and my only other choices would be satellite or cellular, so I'm stuck with them.
It did take a while to figure out what was causing the intermittent DNS failures. "My ISP is hijacking all port 53 traffic" was fairly low on my list of possibilities, I must admit.
Fortunately it's not that hard to run a local resolver that forwards queries to an external resolver on a vps on an alternate port.
I'd switch ISPs, but I live in a remote area and my only other choices would be satellite or cellular, so I'm stuck with them.