Add missing steps for disabling TFTP and DNS

[rh-max]

What changes are you introducing?

Adding missing steps for disabling TFTP and DNS for unmanaged networks.

Why are you introducing these changes? (Explanation, links to references, issues, etc.)

https://issues.redhat.com/browse/SAT-18574

Anything else to add? (Considerations, potential downsides, alternative solutions you have explored, etc.)

Checklists

• I am okay with my commits getting squashed when you merge this PR.
• I am familiar with the contributing guidelines.

Please cherry-pick my commits into:

• Foreman 3.13/Katello 4.15
• Foreman 3.12/Katello 4.14 (Satellite 6.16)
• Foreman 3.11/Katello 4.13 (orcharhino 6.11 on EL8 only)
• Foreman 3.10/Katello 4.12
• Foreman 3.9/Katello 4.11 (Satellite 6.15; orcharhino 6.8/6.9/6.10)
• Foreman 3.8/Katello 4.10
• Foreman 3.7/Katello 4.9 (Satellite 6.14)
• We do not accept PRs for Foreman older than 3.7.

[github-actions]

The PR preview for 49f1757 is available at theforeman-foreman-documentation-preview-pr-3509.surge.sh

The following output files are affected by this PR:

• Installing_Server/index-foreman-deb.html
• Installing_Server/index-foreman-el.html
• Installing_Server/index-katello.html
• Installing_Server/index-orcharhino.html
• Installing_Server/index-satellite.html
• Installing_Server_Disconnected/index-satellite.html

show diff

show diff as HTML

[ekohl]

I don't think this change is correct, but the whole file is confusing in its purpose.

If we analyze the title and the first sentence, that's:

Disabling DNS, DHCP, and TFTP for unmanaged networks

If you want to manage TFTP, DHCP, and DNS services manually, you must prevent {Project} from maintaining these services on the operating system and disable orchestration to avoid DHCP and DNS validation errors.

So the purpose is to have services installed, but managed manually by sysadmin. Then an instruction is given to disable the Foreman Proxy features (DHCP, DNS, TFTP). This effectively means the services may still run, but at least Foreman no longer orchestrates them.

If the intent was to let the sysadmin manage these services themselves, then that should be sufficient. Masking them would be part of a procedure to really remove the services, but I don't think we document that at all today.

[ekohl]

DHCP, DNS, or TFTP. Also, proxy is an upstream word and I don't know for sure how this is branded in downstream.