Q

Do multiple router interfaces affect the amount of IP addresses?

Learn about router interfaces and the assignment of IP addresses in this response from networking expert Chris Partsenidis.

Somebody told me that if a router has four interfaces (let's say four RJ-45 Jacks,) then it will have four IP addresses. Is that true? Can you please elaborate on the IP addresses of routers?
Routers usually have a variety of interfaces, including Fast Ethernet (RJ-45.) Some vendors, such as Cisco, give you the ability to add different types of interfaces depending on your needs. That way, you don't need to change your router to cover new needs.
Firewall.cx logo

Do you have questions about networking, VPN security or VoIP? Then visit Firewall.cx, one of the few websites recommended by Cisco Systems in its world class Cisco Academy program.

Almost all interfaces on a router are configurable with an IP address. Some interfaces, such as the Fast Ethernet you mentioned, can be configured with one or two IP addresses. This way, you can have one physical interface configured to support two logical networks.

For example, the Fast Ethernet interface can have IP addresses 192.168.0.1 and 192.168.1.1 assigned to it. This means both networks (192.168.0.0/24 & 192.168.1.0/24) can 'see' the router.

 

This was first published in July 2008

Dig deeper on IP Networking

Pro+

Features

Enjoy the benefits of Pro+ membership, learn more and join.

Have a question for an expert?

Please add a title for your question

Get answers from a TechTarget expert on whatever's puzzling you.

You will be able to add details on the next page.

0 comments

Oldest 

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

-ADS BY GOOGLE

SearchSDN

SearchEnterpriseWAN

SearchUnifiedCommunications

SearchMobileComputing

SearchDataCenter

SearchITChannel

Close