CCNA
Cisco Certified Network Associate certification resources
How to Configure RIP Passive Interface
By default, the Routing Information Protocol (RIP) sends routing table updates every 30 seconds on all enabled interfaces. In RIP version 1 (RIPv1), these are broadcasts to 255.255.255.255, while RIP version 2 (RIPv2) uses multicasts to 224.0.0.9. However, updates should only be sent on interfaces connected to other RIP-enabled routers to avoid unnecessary traffic. This...
How to Configure Routing Information Protocol (RIP)
Routing Information Protocol (RIP) is a dynamic routing protocol that defines a way for routers to connect different networks using the Internet Protocol (IP) to share information about how to route traffic among these other networks. The Routing Information Protocol (RIP) uses hop count as a routing metric to determine the best path between the source and...
Fixed-Length Subnet Masking (FLSM) Exclusive Explanation
Fixed-Length Subnet Masking (FLSM) is the subnetting method where a network is divided into equal-sized subnets — every subnet uses the same subnet mask and therefore holds the same number of addresses. It’s the first subnetting technique most networking students learn, and it’s the natural starting point before moving on to Variable-Length Subnet Masking (VLSM),...
Classless Inter-Domain Routing (CIDR) Explained
The IETF introduced CIDR in September 1993, through a set of RFCs. RFC 1519 laid out the core addressing and aggregation strategy. RFC 1518 described the overall architecture. RFC 1517 explained why the change was needed in the first place. Together, they replaced the old classful addressing system. RFC 1519 was later obsoleted by RFC...
IPv4 Classful Network Exclusive Explanation
A classful network is a network addressing architecture used in networks since 1981. RFCs 790 and 791, released in 1981, describe how IPv4 network addresses were primarily allocated based on a classification system. The authors of IPv4 addresses set up three classes of network addresses: class A, B, and C for different network sizes. Classful...
Configure a Directly Connected Static IPv6 Route
The directly connected static IPv6 route is the best routing solution when CEF is not working on the router. In the old Cisco IOs before 12.0 versions, this is the best solution to avoid recursive routing. It is also the best in point-to-point networks. It is also the best alternative to using the next-hop IPv6...
Static IPv6 Route Using Next-Hop IPv6 Address
Only the IP address of the next-hop IPv6 is specified in the next-hop static IPv6 route. The exit interface is derived from the next hop. For example, in Figure 1, three next-hop static routes are configured on Router 0. Before forwarding any packet, the router must resolve the route to determine the exit interface to...
IPv6 Route Command: Configuring Static Routes on Cisco Routers
If you already know how to configure a static route for IPv4, configuring IPv6 static routes will feel familiar — the syntax and underlying logic are nearly identical, with only minor differences. IPv6 static routes are configured using the ipv6 route command in global configuration mode. The general syntax is: The parameters here map almost...
How to configure Default Route
A default static route is a route that represents any network, not in the routing table of that router. Routers normally use default routes that are configured locally or learned from another router, using a dynamic routing protocol. A default route is used when there are no other routes that match in the routing table...
How to Configure Directly Connected Static Route
Another way to configure a static route is to use the exit interface to specify the next-hop address. Before the CEF, this method was used to avoid the recursive lookup problem. But now the CEF resolves the recursive lookup problem. In Figure 1, the same topology that we already discussed in the previous lesson is...