[Bug] The --local-addr option is invalid ?

[Baoxd123]

Describe the bug

Even if I added the local addr option following the help instruction, the local address did not change.

To Reproduce

echo "censys.io" | ./zdns A --local-addr 128.192.12.101 //the ip can be anything, because all are invalid

Expected behavior
The src IP should be "128.192.12.101" but no change in the captured packets.

Screenshots
Indeed, the local IP "128.192.12.188" does not exist in my machine, but I can specify it and nothing changed in the captured packets.

[phillip-stephens]

Hey @Baoxd123! Thanks for filing this issue.

You're correct, in this case we're ignoring your specified --local-addr. If you use --verbosity=5, you'll see some logs explaining why:

INFO[0000] using local addresses: [128.192.12.101]
INFO[0000] for non-iterative lookups, using external nameservers: 127.0.0.53:53
INFO[0000] for iterative lookups, using nameservers: 127.0.0.53:53
INFO[0000] no name server provided for external lookup, using  random external name server: 127.0.0.53:53
...
INFO[0000] none of the user-supplied local addresses could connect to name server 127.0.0.53:53, using local address 127.0.0.1

By default if you don't specify any external nameservers with --name-servers, we use whatever DNS resolver is configured in /etc/resolver.conf. It looks like for you that's "resolver":"127.0.0.53". That's a loopback DNS resolver on your host machine. We wouldn't be able to connect to it using your specified 128.192.12.188 so instead of failing and leaving it to the user to try to figure out why, we switch to using a public-facing IP address for your host.