alt Hacker NewsPosting because OpenWRT, possibly others as well, assign .lan names to devices on the LAN by default. People who make use of this might want to follow the application, and, if it goes through, either change the name or make sure queries can't get incorrectly get sent to upstream resolvers.
Regarding that last point, I've had issues with dnsmasq in the past where it was remotely resolving domains even when they were configured to resolve locally. For .lan domains, this could be disastrous because I often send plaintext traffic to them. I did submit a fix/workaround[0], but it's still something to look out for. If anyone knows more about this issue or other ways queries could leak, please share!
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This reminds me of when I used to do IT work for small businesses in college. One printing company I worked for, had about 100 computers on their network, and was using public ipv4 addresses, that they did not own, on their internal network. I forget what range they were using now. But imagine seeing a DHCP server handing out addresses like 142.250.110.1/16 on a LAN and the public ip being something totally different.
It was funny, because when I brought it up to them, it was hard to articulate why it was a problem and I couldn't convince them it was worth the effort of trying to fix. They never ran into a specific issue due to this while I was there but it felt so gross.
.lan should just become reserved
RFC 8375: Special-Use Domain 'home.arpa.' is supposed to be used for this.
https://www.rfc-editor.org/info/rfc8375/