Is there any mechanism to actually implement a subdomain in an mDNS environment using .local?

Posted by ElvisDumbledore@reddit | sysadmin | View on Reddit | 13 comments

I occasionally see offices without AD or DNS setups attempt to add a subdomain to the .local address in Windows. The uri/url they want to use looks like workstation.businessname.local. I can't find or even imagine how this would be implemented on a network of Windows workstations. Sometimes it seems harmless but other times it seems to create problems.

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orev@reddit

The people doing that are improperly using .local probably because they don't know it's already reserved for mDNS. They're overlapping the name, not working within any official method of adding mDNS subdomains.

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retiredaccount@reddit

Or, their implementation and use of .local predates “official” mDNS, which only became standards-track in 2013. Some networks are old, and change comes slowly…or not at all.

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itishowitisanditbad@reddit

Some networks are old

Fun post every so often where people compare the first registered date of the domain of their workplace, there are some real old ones out there.

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TYGRDez@reddit

Exactly this.

I hate that our domain is using .local, but it was set up nearly 20 years ago and management won't sign off on the "unnecessary" work it would take to rebuild everything, when it's all "working fine"

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Arudinne@reddit

Frankly I have better things to do than fuck with a domain that is otherwise working just fine.

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ADynes@reddit

Same. Been ABC.local internally for 20+ years and ABCompany.com externally for email. I have yet to have an issue, it works fine. Literally the only thing I have to watch out for is creating a new user and switching it over to abcompany.com and not leaving the abc.local default.

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Ninjabeaver212@reddit

This is my company to a T. We're in the middle of disabling mDNS internally as it has been used for MitM attacks during our yearly pen tests. Turns out disabling mDNS wrecks havoc with cross domain/forest communication when DNS forwarders are configured pointing to another .local domain. No this makes ZERO sense when you understand how mDNS actually works, but this is the exact issue we've ran into in our environment. We spent an entire month researching this with multiple vendors only to come up completely empty handed and everybody involved stumped.

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flyguydip@reddit

Apple bonjour and .local domain conflict - Software & Applications - Spiceworks Community https://community.spiceworks.com/t/apple-bonjour-and-local-domain-conflict/147190

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cacheclyo@reddit

Yeah, this. .local in Windows-land is kind of a weird mess because you’ve got:

mDNS using .local as reserved
Old habits from people treating .local as a fake internal AD zone

When someone does workstation.businessname.local with no proper DNS or AD, Windows will try a mix of things: mDNS, LLMNR, NetBIOS, search suffixes, whatever. Sometimes it “works” by accident, sometimes you get random timeouts and name conflicts.

There isn’t some clean mDNS hierarchy where you can just bolt on subdomains like that. If they actually want workstation.businessname.something, they should either run real DNS with a proper domain they own, or pick literally anything that isn’t .local and isn’t a public TLD. Using .local that way just guarantees weird edge cases.

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Dont use .local outside mDNS and get a proper domain or use .internal.

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flyguydip@reddit

Also, try not to use .local anymore...

Apple bonjour and .local domain conflict - Software & Applications - Spiceworks Community https://community.spiceworks.com/t/apple-bonjour-and-local-domain-conflict/147190

How stupid is that, right?