On 13 Jan 2017, at 09:40, Gerriet M. Denkmann <gerri...@icloud.com> wrote: > > iOS (10.2) app does: > > SERVICE_TYPE = 1 to 63 ascii chars; no spaces; no ‘.’; no ‘[‘; can use ‘_' > or '-'; case insensitive > Note: I did not find these rules documented anywhere, they are just the > result of trial and error.
[snip] > If SERVICE_TYPE is more than 63 chars, then > -[NSNetServiceBrowserDelegate netServiceBrowser:didNotSearch:] will complain > with BadArgument. > > Now I see in iOS 10.2 (maybe was there before): > com.apple.mDNSResponder AllINFO > Bad service type in ._GmdEcho890123456._tcp.local. Application protocol name > must be underscore plus 1-15 characters. See > <http://www.dns-sd.org/ServiceTypes.html> > > But it still works. > > So: > > 1. what is the real constraint of SERVICE_TYPE: > 1a: underscore plus 1-63 characters (NSNetServiceBrowser) > 1b: underscore plus 1-15 characters (mDNSResponder) > > 2. is this documented anywhere? The 63 character limit is from the DNS, specifically RFC 1035 section 2.3.1, which says: Labels must be 63 characters or less. This applies to each label in a domain name. The 15 character limit is specific to SRV records and comes from RFC 6763, section 7.2, which says: The Service Name <sn> may be up to 15 bytes, plus the underscore… I don’t know if *Apple* has documented these anywhere in its documentation, but they are certainly in the relevant RFCs. Kind regards, Alastair. -- http://alastairs-place.net _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
