I have a web server running on IIS Express.

I modified the bindings in my IIS instance to run on PORT:COMPUTERNAME and also added a rule to the firewall to allow inbound requests on that port.

When I navigate to http://COMPUTERNAME:PORT on a windows laptop over LAN, I get my webpage, however the same thing on my OSX never connects. I've tried http://COMPUTERNAME.local:PORT and http://IP4ADDRESS:PORT to no avail.

I can ping the ip4 of the server and get a response just fine.

I'm not running on a domain, and both computers are in the same workgroup.

Any Ideas?


OS X will only use Microsoft-proprietary name services (NetBIOS Name Service, WINS, LLMNR) when connecting to Microsoft-proprietary protocols/services like SMB/CIFS. It generally won't use Microsoft-style name services when resolving host names for standard Internet protocols like HTTP.

Note that to Windows machines, .local means Microsoft's LLMNR, not the IETF standards-track ZeroConf mDNS (which Apple calls Bonjour). To Macs, .local means IETF ZeroConf mDNS (Bonjour).

So to solve your problem, add an entry for your IIS COMPUTERNAME in the /etc/hosts file on the OS X machine, or point the OS X machine at a DNS server that has a proper mapping for COMPUTERNAME.

  • What you're saying does make sense, but wouldn't the name service conflicts not matter if I tried to connect via IP address as opposed to the computer name? As a side note, I tried adding an entry in the /ect/hosts/ file (192.168.1.IP Tab COMPUTERNAME) and haven't gotten any results (flushed DNS for good measure as well). I'll try the DNS mapping. Thanks – Ken Lund Jul 15 '15 at 7:31
  • @KenLund Well, in the IP address case, it might connect to IIS, but not load the website correctly, since it wouldn't be able to fill in the HTTP/1.1 "Host:" header correctly. If you don't have a default website configured in IIS (i.e. if IIS is configured for hosting multiple virtual websites with different hostnames on the same IP address), then your Mac browser might be able to make an HTTP connection to IIS, but it would receive an HTTP error from IIS because it put "Host: IP4ADDRESS" instead of "Host: COMPUTERNAME" in the HTTP request headers. – Spiff Jul 15 '15 at 7:39
  • Rather new to this site, so I'm not sure what the correct way of marking what the correct answer was considering it was your comment, but it did end up being an IIS issue. Changed the site to the default and everything figured itself out. – Ken Lund Jul 15 '15 at 7:47

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