25 minv1.0

Networking and secure remote use

Learning objectives

Inspect interfaces, routes, listening ports, and name resolution
Explain secure SSH access and file transfer

1 Objective→ 2 Learn→ 3 Example→ 4 Practice→ 5 Verify→ 6 Continue

How to study this lessonUnderstand the idea first. Use the example to see the behaviour, practise where provided, then make sure you can explain the result before continuing.

Explanation

Follow the connection

To reach a remote engineering server, the system resolves its name to an IP address, selects a route, connects to a destination port, and verifies the server identity. A failure at each step produces different evidence.

Commands you will use

Command	What it does	Example
`ip address`	Shows interface addresses.	`ip address`
`ip route`	Shows routing decisions.	`ip route`
`ss`	Shows sockets and listening ports.	`ss -ltn`
`getent hosts`	Uses configured name resolution.	`getent hosts server.example`
`ping`	Tests basic reachability when allowed.	`ping -c 3 server.example`
`ssh`	Opens an encrypted remote shell.	`ssh user@server.example`
`scp`	Copies files through SSH.	`scp run.log user@server:project/logs/`
`rsync`	Synchronizes selected files efficiently.	`rsync -av reports/ user@server:reports/`

Before accepting a new SSH host key, verify its fingerprint through an approved channel. Keep private keys private. Confirm both local and remote paths before using scp or rsync.

Worked example

These checks do not require a remote account:

ip address
ip route
ss -ltn
getent hosts localhost
command -v ssh
ssh -V

Expected result: the commands show local interfaces, at least one route, listening TCP ports, a localhost resolution, and the installed SSH client version.

RTL/DV use

Engineers commonly edit locally while builds and regressions run on remote compute servers. Transfer only approved project files, exclude generated data when appropriate, and never publish private hostnames or addresses in course evidence.

Common mistakes

Accepting an unexpected or changed host key without verification.
Reversing local and remote paths in scp.
Assuming blocked ping means the application service is unavailable.
Copying confidential RTL or logs to an unapproved system.

Check yourself

Why must an SSH host-key fingerprint be verified through a trusted channel?

Engineering practice

Practice: Networking and secure remote use

Task→Run / reason→Check result→Explain why

Record a local address, default route, and one listening port without sharing private values publicly. Explain the checks that occur before an SSH session starts.

Practice work is non-certified and is not stored by ASIC Campus.