Configure and verify inside source NAT using static and pools.

Objective 4.1 sits in IP Services, which carries 10% of the CCNA exam. The questions below are original, written from the official objective title above, and each explanation cites the Cisco page it rests on.

Objective title verbatim from the official objectives. Cisco exam page ↗

A worked example

Shown solved, with the whole explanation open: this is what every question here carries.

4-1IP ServicesModerate

A router was configured for dynamic inside source NAT with a pool. No inside host has sent traffic toward the outside yet.

Router# show ip nat translationsPro Inside global      Inside local       Outside local      Outside globalRouter#

Why is the table empty?

Dynamic entries appear only after matching traffic passesCorrect · your answerCorrect. Nothing has crossed the router yet, so no binding exists.

Entries appear only once the overload keyword is addedThe overload keyword decides whether port numbers are tracked alongside each address; it has no say in when the first entry is created.

The access list must permit any for entries to appearAn access list scoped to a few subnets still builds entries for the addresses it permits. Cisco warns against permit any because of resource consumption.

The pool must be exhausted before entries are listedPool exhaustion shows up as addresses already in use and dropped packets for later hosts. It would fill the table, not leave it blank.

Correct.

Checked against cisco.com, August 2026

Concept

A translation table is a record of sessions, not a copy of the configuration. A mapping written by hand sits in the table from the moment it is configured, while anything the router builds on demand exists only once a packet the rules select has actually arrived.

Why A

The pool and the access list only define what may be translated. Until a packet from a permitted inside address is switched toward the outside interface, the router has nothing to bind, so the display returns no rows at all. A static mapping would already be listed here, and that difference is exactly what the empty output shows.

Source

With dynamic NAT, the translation table in the router is initially empty and gets populated once traffic that needs to be translated passes through the router.

Cisco: Configure Network Address Translation, checked August 2026

#nat#dynamic-nat#show-ip-nat-translations

Now you: objective 4.1 questions

No account needed. The explanation opens when you answer.

Sample question 1 of 3

4-1IP ServicesHard

A router carries the static mapping and translation entry below.

ip nat inside source static tcp 172.16.10.8 8080 172.16.10.8 80 Router# show ip nat translationsPro Inside global      Inside local       Outside local      Outside globaltcp 172.16.10.8:80     172.16.10.8:8080   ---                ---

Which packets does the router send to 172.16.10.8:8080?

Sample question 2 of 3

4-1IP ServicesEasy

A router maps each internal address to a distinct public address, invisibly to end users. Which NAT variant is that?

Sample question 3 of 3

4-1IP ServicesEasy

Thirty hosts behind a home router share one public IP address simultaneously. Which NAT form makes that possible?

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Read the sources

These are the official pages the questions above cite. Reading them is studying the objective from the primary source, which is what the explanations point you toward anyway.

A worked example

Now you: objective 4.1 questions

Read the sources

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