Unable to locate package rssh

[abidfakhrealam]

Current Behavior

I followed this :https://www.archivematica.org/en/docs/archivematica-1.15/admin-manual/installation-setup/customization/dashboard-config/#admin-dashboard-atom

in the AtoM server configuration section it is mentioned that: :
Now, it’s time to configure the AtoM server so Archivematica can send the DIPs using SSH/rsync. For that purpose, you will create a user called archivematica and we are going to assign that user a restricted shell with access only to rsync:

$ sudo apt-get install rssh
$ sudo useradd -d /home/archivematica -m -s /usr/bin/rssh archivematica
$ sudo passwd -l archivematica
$ sudo vim /etc/rssh.conf
Add the SSH key that we generated before:

$ sudo mkdir /home/archivematica/.ssh $ chmod 700 /home/archivematica/.ssh/ $ sudo vim /home/archivematica/.ssh/authorized_keys // Paste here the contents of id_dsa.pub $ chown -R archivematica:archivematica /home/archivematica

is there any proper guide to configure the AtoM with Archivematica.
I have install the AtoM and Archivematica in two different server AWS ec2 instance Ubuntu 22.04

Expected Behavior

When I run this command in AtoM server to configure the rssh it through this error
root@IP:/opt# sudo apt-get install rssh
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
E: Unable to locate package rssh

Possible Solution

No response

Context and Notes

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Version used

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Operating System and version

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Default installation culture

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PHP version

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Contact details

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[fiver-watson]

For the Maintainers: some additional context provided by @amayita via the AtoM user forum:

rssh was inscure and has been abandoned upstream, and removed from Ubuntu.
Useful context: https://superuser.com/questions/1678816/cannot-install-rssh-on-ubuntu-virtualbox
We need to update the docs, a candidate would be rush (should work the same, may need to be configured by you), but we obviously have not tested it yet.