Packer SSH communicator `ssh_port` argument value is ignored

[mschuchard]

Overview of the Issue

When specifying a value for the argument ssh_port, the argument value is ignored, and instead the port is chosen from the range specified by host_port_min and host_port_max is selected. I have repeated this multiple times to verify the behavior.

Reproduction Steps

packer build

Plugin and Packer version

1.8.3 and 1.0.4

Simplified Packer Buildfile

source "virtualbox-vm" "ubuntu" {
  ssh_host = "127.0.0.1"
  ssh_port = "2222"
}

Operating system and Environment details

n/a

Log Fragments and crash.log files

2022/09/08 15:19:29 packer-plugin-virtualbox_v1.0.4_x5.0_linux_amd64 plugin: 2022/09/08 15:19:29 [INFO] Attempting SSH connection to 127.0.0.1:3171...
2022/09/08 15:19:29 packer-plugin-virtualbox_v1.0.4_x5.0_linux_amd64 plugin: 2022/09/08 15:19:29 [DEBUG] reconnecting to TCP connection for SSH
2022/09/08 15:19:29 packer-plugin-virtualbox_v1.0.4_x5.0_linux_amd64 plugin: 2022/09/08 15:19:29 [DEBUG] handshaking with SSH
2022/09/08 15:19:29 packer-plugin-virtualbox_v1.0.4_x5.0_linux_amd64 plugin: 2022/09/08 15:19:29 [DEBUG] SSH handshake err: ssh: handshake failed: read tcp 127.0.0.1:42718->127.0.0.1:3171: read: connection reset by peer

[mschuchard]

Also noticing that setting ssh_password or ssh_certificate_file argument values results in authentication method [none] during ssh communicator attempts, so this could be multiple ssh communicator arguments.

[texhnolyze]

I have the same issue with ssh_host in virtualbox-iso, which I assume uses the same SSH logic.

I think your problem is twofold:
If I understand the docs for skip_nat_mapping correctly options like ssh_host and ssh_port are only used if you configure skip_nat_mapping = false.

However even with this setting it would still use the default ssh_host of 127.0.0.1 for me, but explicitly setting communicator = "ssh" fixed this issue for me. But I think that should still be considered a bug.

My current config:

source "virtualbox-iso" "ubuntu2404" {
  ...
  communicator           = "ssh"
  skip_nat_mapping       = true
  ssh_host               = "172.30.16.1"
  ssh_port               = 2222
  # Explicitly set port forwarding from 2222 -> 22
  # only needed, because I'm running packer in WSL, but VBox under Windows
  vboxmanage             = [
    [ "modifyvm", "{{.Name}}", "--natpf1", "ssh,tcp,172.30.16.1,2222,,22" ],
  ]
}