I'd like to share a disk to a Mac on the WAN using the smb protocol. To share the same disk over afp, I simply forwarded port 548 to be available to the WAN. For smb, I've tried forwarding every port that seems to be related, but am unable to mount the disk.

Please answer if you are able to forward access to your disk to another network, and the steps you took to do it. Maybe it's more than forwarding ports.

Thank you


You need the following ports:

  • UDP 137/138
  • TCP 137/139/445

If you are attempting to expose your SMB shares over the Internet, it's not going to work. The UDP ports are not routable over the public internet.

You either need to have a private link between the two sites or a VPN. Even with this, it's a very inefficient method. You are far better off with a cloud based solution.

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    I've tried all of these ports and it didn't work. Was this something you were able to reproduce? this isn't going through the internet just from one LAN to its WAN. – Walrus the Cat Feb 14 '18 at 0:46
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    Still, UDP is not routable because it's a broadcast protocol (there's no specific destination like TCP), so you have to make the WAN part of the same subnet. Too much of a PITA. Previously we would have two file servers and sync them with something like rsync, but now with AD in the cloud and features like OneDrive for Business and servers like SharePoint, those days are long gone. – Allan Feb 14 '18 at 0:53
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    well i appreciate your input but the port-forwards don't work. basically i am under the impression that smb is a faster/superior protocol and i need to share a time machine disk through two networks (can use it with afp). any advice on whether/how to pursue this? – Walrus the Cat Feb 14 '18 at 2:55
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    Your best bet is FedEx the drive to you. After that, make an image of the drive using dd then transfer it via scp/sftp next in line is VPN, but SMB over VPN has very poor performance. – Allan Feb 14 '18 at 11:08

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