Mounting SMB1 shares after kernel 5.15

Linux kernel 5.15 dropped support for NTLMv1, a weaker authentication algorithm.

As a consequence, if you have old hardware that only supports SMB1 (such as Apple’s Airport Time Capsule), you may have trouble mounting them on recent distributions like Ubuntu 22.04.

Some workarounds are:

  • Downgrading or patching the kernel.
  • Using an extra device between the SMB1 hardware and your client to do the mount.
  • Switching from SMB to another protocol, if the device supports it. For example, the Time Capsule is reachable via AFP.

An easy path, however, is to enable guest mode on that hardware, if available. Then, just mount it on your client with something like this:

$ sudo mount -t cifs -o guest,vers=1.0 //SERVER/PATH /mnt/path

Sure, you lose the password “protection”, and you may be left with only one share. However, taking in account that the security for SMB1 and NTLMv1 is broken for a long time, that’s not much of a loss.

More information is available here.