veth tips — authorized virtual-ethernet-pair literacy

Snapshot

Tip checklist (authorized only)

1. Confirm you may create/delete veth pairs on the lab host (syllabus box you own; needs CAP_NET_ADMIN).
2. Prefer documenting who / why / ticket before any ip link add — never rewrite production links without change control.
3. Record short factual notes; quote short Evidence (veth name + peer name + netns — never secrets).
4. Optional: link peer → ip-link-tips when the syllabus zooms on general link admin vs veth pairs.
5. Optional: netns peer → ip-netns-tips / bridge-tips when the syllabus zooms on namespace moves or bridge enslavement.
6. Prefer disposable lab pairs for drills; quote non-secret labels afterward as Evidence.
7. Prefer ip -d link show type veth read-back — refuse unauthorized foreign-host cookbooks.
8. Stop at literacy — no attack or unauthorized network-bypass cookbooks.

Allowed framing

• Classroom labs reviewing ip link add type veth on disposable hosts.
• Binding short factual notes as Evidence (name + peer + netns — no secrets).
• Documenting expected vs observed veth peer pairs for authorized notes.
• Comparing veth ↔ ip-link / ip-netns / bridge / macvlan peer tip pages under one binder.
• Testing syllabus-approved lab pairs only when change control authorizes that drill on lab resources.

Scope we will not cover

• No crack/pirate/keygen via veth.
• No intentional unauthorized veth wiring against foreign hosts.
• No secret-theft or credential harvesting from link dumps.
• No cookbooks that use veth as an attack step against production without authorization.
• No veth framed as a network-bypass against systems you do not own.

Beginner path (authorized only)

1. Obtain one syllabus-approved disposable lab host with iproute2 available.
2. Prefer a throwaway lab netns (ip-netns-tips) before touching real NICs.
3. With authorization, create/list lab veth pairs; quote selected name/peer labels as Evidence.
4. Optional: peer tip pages above when the syllabus asks.
5. Stop at literacy — no attack or unauthorized network-bypass cookbooks.

Practical notes for authorized labs

• veth creates paired virtual Ethernet devices — keep Evidence labels distinct from ip-link-tips and macvlan-tips.
• Pair with ip-netns-tips when the syllabus moves one peer into a namespace.
• ip -d link show type veth is a great read-back drill — document selected pairs without dumping unrelated privileged state.
• Prefer documenting veth names, peer names, and netns membership the syllabus authorized.
• Never commit link dumps with secrets or proprietary host inventories to git — even for labs.

FAQ-aligned refusals (quick)

• Foreign-host veth → refuse.
• Unauthorized network-bypass / hostile-wiring attack cookbooks → refuse.
• Attack/credential-theft framing → refuse.

For legal, authorized and educational use only.

FAQ

Sources