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nightwatch avatar Ubuntu

SSH Over VBox NAT NOT Working Ubuntu 20.04 Host (desktop) Ubuntu 20.04 server (guest)

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nightwatch

I can get internet on guest by setting vbox adapter 1 to bridged network adapter

and host-guest communication works when I set adapter 2 as a host-only adapter

This is sufficient if I don't want to use a firewall, but I do... with this solution I need to constantly fiddle with UFW to allow adapter 1 communication.

After some reading, I realized that I should be able to set up adapter 1 as a nat adapter and configure port forwarding as shown below.

name|proto| host ip   | Host port| Guest IP     | Guest Port
SSH | TCP | 127.0.0.1 | 2522     | 192.168.52.1 | 22

This way I should be able to ssh into the guest using: ssh -vvv -p 2522 -i ~/.ssh/id_rsa [email protected]

My problem is that this method simply freezes without explanation.

OpenSSH_8.2p1 Ubuntu-4ubuntu0.4, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/user/.ssh/config
debug1: /home/user/.ssh/config line 41: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 127.0.0.1 is address
debug2: ssh_connect_direct
debug1: Connecting to 127.0.0.1 [127.0.0.1] port 2522.
debug1: Connection established.
debug1: identity file /home/user/.ssh/id_rsa type 0
debug1: identity file /home/user/.ssh/id_rsa-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_8.2p1 Ubuntu-4ubuntu0.4

(I tested with UFW disabled.)

Everything, says this should work, but it doesn't... any guesses?

If ssh over NAT works, I can ssh into the box and have host-guest communication without constantly editing my firewall.

Progress: According to @steeldriver's suggestion and this post the correct ip address for port forwarding should be Guest IP = 10.0.2.15

However, when using that that address, ssh can't connect:

OpenSSH_8.2p1 Ubuntu-4ubuntu0.4, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/dragonpharaoh/.ssh/config
debug1: /home/dragonpharaoh/.ssh/config line 41: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 10.0.2.15 is address
debug2: ssh_connect_direct
debug1: Connecting to 10.0.2.15 [10.0.2.15] port 2522

Adapter 2 Host-only This is my host-only adapter config: enter image description here enter image description here

Adapter 1 NAT enter image description here

Port Forwarding enter image description here

This is current output of #ifconfig inside the guest enter image description here

Netstat confirming Vbox listening port enter image description here

NOTE: Both the host is fairly fresh install (less than a month) and the guest was made today

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matigo
For the Host-only adapter, have you created a device (probably called `vboxnet0`) and set the promiscuous mode to "Allow All"? The IP address should be something like `192.168.56.1` rather than the IP address that you are using ...
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steeldriver
Is your NAT guest IP in the same range as your host network? The default NAT setup would use a completely different private LAN range, such as `10.x.x.x` iirc. I can imagine SSH hanging if packets are getting misrouted by an addressing overlap.
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nightwatch avatar
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nightwatch
@matigo I tried your suggestion... same problem, still freezes
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nightwatch
@steeldriver the guest NAT ip is 10.0.2.15 I am testing it now... one sec..
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nightwatch
@steeldriver When I use 10.0.2.15 for port forward. I can't ping and/or ssh to it...
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nightwatch
According to this post https://www.xmodulo.com/access-nat-guest-from-host-virtualbox.html @steeldriver is correct. The netstat command even confirms vbox's listening port on my machine.. I will edit my post above because the ssh output is different..
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steeldriver
I think we need more information about how you set up the network - NAT netmask, DHCP and so on. You can use 2 distinct 192.168.x.0/24 networks for host and NAT if you wish - using 10.x.x.x was just a suggestion to try since it's unambiguously different from any 192.x.x.x range.
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nightwatch
one sec... screenshots coming
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nightwatch
I figured it out fellas... thanks for your help... the problem was user error. The actual ssh command has to be ssh -p 2522 <user>@127.0.0.1 (you MUST use the host ip, it cannot be host-only adapter ip, it can not be the NAT ip, it must be the host ip in the ssh command everything else fails because it can resolve
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nightwatch avatar Ubuntu
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nightwatch

The settings for SSH over NAT in my post are all correct.

The error was the ssh command that I was using:

the ssh command can not be the host-only adapter ip
ssh -p 2222 <login>@192.168.52.1 <- will not resolve

the ssh command can not be the nat adapter ip that is assigned to the vbox
ssh -p 2222 <login>@10.0.2.15 <- will not resolve

The SSH Command MUST Be:
ssh -p 2222 <login>@127.0.0.1

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