How to make Windows' Bonjour resolve foo.bar.local subdomains created by Avahi

Question

Why can't Windows' Bonjour (the Apple one) automatically resolve foo.bar.local, when Ubuntu and macOS can?

foo.local instead is resolved without issues by every OS.

Here's my avahi-daemon.conf:

[server]
host-name=foo
domain-name=bar.local
...

This discussion mentions that Windows' Bonjour implementation does not support aliases, is this the culprit?

How does this tool differ from my solution?

EDIT: I don't want to set an alias. foo.bar.local is different from bar.local. I just want to have different hostnames under the same "domain". For example, foo.bar.local is 192.168.0.8 while foo1.bar.local is 192.168.0.9. I won't have foo.local, bar.local and foo.bar.local all in the same network. I will use foo.bar.local, with only foo varying (*.bar.local)

score 0 · Answer 1 · answered Aug 23 '18 at 15:28

From my current findings, this seems to be intentional. Excerpt from the source code (mDNSResponder-878.30.4, function NSPLookupServiceBegin in mdnsNSP.c):

    // <rdar://problem/4050633>

    // Don't resolve multi-label name

    // <rdar://problem/5914160> Eliminate use of GetNextLabel in mdnsNSP
    // Add checks for GetNextLabel returning NULL, individual labels being greater than
    // 64 bytes, and the number of labels being greater than MAX_LABELS
    replyDomain = translated;

    while (replyDomain && *replyDomain && labels < MAX_LABELS)
    {
        label[labels++] = replyDomain;
        replyDomain     = GetNextLabel(replyDomain, text);
    }

    require_action( labels == 2, exit, err = WSASERVICE_NOT_FOUND );

It returns an error if the name has more than two labels, as in the case of foo.bar.local.

In my tests, I just removed the last line. With the new build, it resolved names with multiple labels successfully. I did not yet encounter any side-effects so far.

Has anybody an idea about the intention behind not resolving multi-label names?

How to make Windows' Bonjour resolve foo.bar.local subdomains created by Avahi

1 Answers1