This is an original planning guide. It is not a vendor manual, an official standard, or legal advice. Example addresses use documentation ranges. Review every command before you paste it.
What this hour is for
TCP is a connection with a handshake and retransmission. UDP is a datagram. A timeout means different things. A DNS query is often UDP. A web page is TCP. Some applications use both.
Write which one the application uses. Do not open both in a firewall because you are unsure. Look it up on the port sheet and then confirm with the application owner.
Loss hurts both, in different ways. TCP slows down. UDP does not repair itself. The loss page is the measurement. This page is the label.
One application.
The change you can finish
Apply nothing during the writing of the note. When the lab window opens, it is one change on the device named in the ticket. Read the draft, then the device, then decide.
Rollback is the file or the revision you saved first. You do not invent a rollback after the only copy is gone.
- Name the application.
- Say TCP, UDP, or both, and which ports.
- Confirm with the owner if you are unsure.
- Write the firewall implication in one line.
- Do not open extra ports.
- Stop.
Mistakes that outlive the command
TCP vs UDP goes wrong in a small set of ways. The list is here so the ticket can forbid them before the window.
- Both protocols opened because of doubt.
- UDP silence treated exactly like a TCP reset.
- The application unnamed.
- A scan to decide.
Decisions to write down
One decision for TCP vs UDP: The protocol is written. The ports are written. No extra port was opened. No scan was used to decide. And one application.
Checks before you call it done
Confirm this before you call the change done: The label is in the ticket. The owner agrees or the doubt is written. The firewall line is one sentence. Nothing was opened. And measurement waits for the loss page if needed. If one of those fails, stop.
Label TCP or UDP.
Do not open both because you are unsure.Before you leave the device
TCP vs UDP ends when the hostname on the device matches the hostname in the ticket. If it does not, you are on the wrong box. Stop. A command that succeeded on the wrong box is not progress.
The draft stays a draft until a person has read the names in it. A generator does not log into the device and does not know which interface is the uplink. You delete a line that names a device, a zone, or a prefix you did not write down.
0.0.0.0/0 is not kept because a sample included it. A source you can say is the source you keep. 192.0.2.0/24, 198.51.100.0/24, 203.0.113.0/24, and 2001:db8::/32 are documentation. They belong in the note. They are not prefixes you type onto a production device because they appeared in a draft.
prompt-for-this is a reminder that a secret is missing. It is not a password, a key, a community string, or a pre-shared key you save in the ticket or in git. The real secret stays in the store.
One change is the window. A VLAN and a routing protocol and a VPN do not share it. If two things move and the result is wrong, you will not know which one did it. The next feature waits for its own page.
If the same step fails twice, stop for the day. The failure is the result. Adding a forum command beside a half-applied config produces a device nobody can rebuild. Restore the copy you took first.
A second person reads the device name and the change aloud. If they cannot find them in the ticket, the note is not done. Silence is not agreement. Then leave the device alone.
This page is a planning guide. It is not a vendor manual, not an official standard, and not a permission to touch a network you do not administer. The pillar guide owns the wider design. This page owns one lab proof.
Tools for this guide
This guide does not name a browser tool. The pillar it belongs to links the calculators for the neighbouring work.
Related pillar guides
More in this cluster
The pillar for this page, and the next published pages filed with it.