I'm trying to connect to an SMB share on a Windows machine from a Mac. The SMB is running on port 445. Apparently the Mac is trying to connect on ports 137 through 139.

How can I configure my Mac client to connect on port 445?

  • Have you verified that port 445 is open on the Windows machine? You an test at the command line with telnet 445. – Doug Harris Aug 19 '10 at 16:05
  • Indeed it is... – Joe Aug 19 '10 at 16:21

Try adding the port number to the URL.

From the "Go" menu in Finder, choose "Connect to Server..." (or simply hit command-K).

In the "Server Address:" field, enter


(replacing the IP address as appropriate)

  • Unfortunately that's the first thing I tried! Doesn't seem to work. – Joe Aug 19 '10 at 15:12

What version of OS X are you using? I tried this on my Mac (v10.6.4), and it tried port 445 first, and only tried 139 when it got no answer over 445. Here's a tcpdump of me (at, trying to connect to "smb://" (which doesn't exist):

Gordons-MBP:~ gordon$ sudo tcpdump -q -ien1 -n tcp port 137 or 138 or 139 or 445 
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on en1, link-type EN10MB (Ethernet), capture size 65535 bytes
18:17:17.732221 IP > tcp 0
18:17:18.705177 IP > tcp 0
18:17:19.706158 IP > tcp 0
18:17:19.732350 IP > tcp 0
18:17:20.707090 IP > tcp 0
18:17:20.707209 IP > tcp 0
18:17:21.708314 IP > tcp 0
18:17:21.708435 IP > tcp 0
18:17:22.709483 IP > tcp 0
18:17:22.709556 IP > tcp 0
18:17:23.709971 IP > tcp 0

Also, note that SMB on ports 139 and 445 are actually different protocols: port 139 is SMB over NetBIOS over TCP, while 445 is SMB directly over TCP ("direct host SMB"). So if there is something preventing your Mac from using port 445, it's not just a matter of changing the port number...

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.