Networking · Lesson 12 of 26 · 8 minutes

Interface baseline

Record a basic network baseline.

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Your objectives

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1
Capture addresses
Run ip addr | tee lab/ip-baseline.txt.
Hint & worked example
Inspect simulated interface and route state. Copy a stream both to a file and standard output; -a appends.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
ip addr | tee lab/ip-baseline.txt
```
Remember: An interface address, a route, and a reachable service are separate parts of connectivity. tee can overwrite a file even though the output is also visible on screen.
2
Read baseline
Run cat lab/ip-baseline.txt.
Hint & worked example
Read one or more files to standard output without editing their contents.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
cat lab/ip-baseline.txt
```
Remember: Reading a source file should precede changing it; avoid printing real secrets.
3
Show route
Run ip route.
Hint & worked example
Inspect simulated interface and route state.
The command outcome must match the task, including successful access or the explicitly requested failure.
```
ip route
```
Remember: An interface address, a route, and a reachable service are separate parts of connectivity.

Understand the pattern

Junior operators build confidence by gathering evidence before changing systems.

ip: Inspect simulated interface and route state.
An interface address, a route, and a reachable service are separate parts of connectivity.
tee: Copy a stream both to a file and standard output; -a appends.
tee can overwrite a file even though the output is also visible on screen.
cat: Read one or more files to standard output without editing their contents.
Reading a source file should precede changing it; avoid printing real secrets.

Worked example and expected result

$ ip addr | tee lab/ip-baseline.txt

1: lo: <LOOPBACK,UP> mtu 65536
    inet 127.0.0.1/8 scope host lo
2: eth0: <BROADCAST,UP> mtu 1500
    inet 10.20.30.40/24 scope global eth0

Exit status: 0. The command completed successfully in the training fixture.

$ cat lab/ip-baseline.txt

1: lo: <LOOPBACK,UP> mtu 65536
    inet 127.0.0.1/8 scope host lo
2: eth0: <BROADCAST,UP> mtu 1500
    inet 10.20.30.40/24 scope global eth0

Exit status: 0. The command completed successfully in the training fixture.

$ ip route

default via 10.20.30.1 dev eth0 proto static
10.20.30.0/24 dev eth0 proto kernel scope link src 10.20.30.40

Exit status: 0. The command completed successfully in the training fixture.

Try a variation

Repeat this workflow in the sandbox with a different scratch filename. Keep the system fixtures unchanged and compare the observed output with your expectation before moving on.

Explain it

In “Interface baseline”, which interpretation is safe?A command appearing in history proves it completed successfully.A successful first check guarantees that every dependent service is healthy.Reading a source file should precede changing it; avoid printing real secrets.

Apply it elsewhere

Before adapting the cat workflow from “Interface baseline” to another server, what should you do?Skip output inspection whenever the command is familiar.Confirm the current directory, target identity, permissions, and the installed command behavior first.Paste the training paths unchanged into production.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

Next: Listener baseline Try an incident drill

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