Per the split-horizon rule, don’t send an update back on the interface it was received on What is the challenge here? In addition to bandwidth usage and system resources consumption, Split horizon helps prevent...
Read More
RIP: do not split it then… and unleach the power of the “network” command
In RIP domain routers R1 and R2 exchange information about loopback 0 and 1 networks Router RIP command “network 0.0.0.0” hints routers to add all ip enabled interfaces to the update list and include...
Read More
Multicast routing: From the source… Part 3
We build on our discussion from the previous blogs The test topolgy How R3 handles Server2 source multicast trafic? R3 is the only UP router It’s mroute table show a correct source and incoming...
Read More
Static routing metric
Both R1 and R3 advertise 13.13.13.13/32 network into RIP domain R3 is configured to offset all network updates via interface fa1/0 by 10 R2 receives R3 route with a metric of 11 hops A...
Read More
5 Minutes
Multicast routing: PIM dense… Part 2
Server2 is 3 hops away from its receivers R3 receives the multicast and forwards it to its forwarding list interfaces At R2 At R2 the outgoing interface list includes also the incoming interface The...
Read More
Adertised RIP learnt routes
In the topology Router R3 receives 1.1.1.1/32 route information from R2 This route gets next into the routing table But what if R2 installed another protocol or source same route (same subnet and mask)...
Read More
RIP flush time
By default RIP sends updates each 30 seconds In this lab we change the value of the invalid timer to 90 seconds What happens if we filter RIP updates R2 sends over fa0/0 link?...
Read More
RIP maximum equal cost paths feature
In this lab, we check how maximum equal paths feature works in RIP In this lab R2 advertises 2.2.2.2/32 subnetwork to R1 via RIP. R1 processed three equal paths through interfaces fa0/0, fa1/0 and...
Read More
Multicast routing: a step by step… Part 1
In the above test lab, Servers send multicast trafic to both clients. In IPv4, multicasting servers uses class D range of addresses: 224.0.0.0-239.255.255.255. Some addresses are well known and others for specific use… In...
Read More
Routing from scratch… Part 0
The person in A wants to join its colleagues in location B through the network topology described in the below figure. This person needs to go back home at the evening! ” This person...
Read More
SSL VPN to my home network
Using only my Box (FTTH), I’m able to access my home network (box Lan subnet) by simple NAT redirection from any internet location. More precisely, I connect to as many hosts, residing in my...
Read More
What is the best way to subnetting?
Given a network ip address what would be the optimal subnetting method? optimal, such as to use the less possible ip addresses, the less possible subnets, a subnet per vlan, multiple subnets per vlan,...
Read More
Cisco HSRP in detail
RFC 2281, What does RFC 2281 say about Cisco HSRP that may affect the IP traffic flow process? Lab setup, Let us analyze the IP traffic forwarding process in our lab setup: The logical...
Read More
My first scapied IPv6 packet
The idea of this lab is to craft an IPv6 packet from scratch using Python and Scapy library. The IDE I use is JetBrains PyCharm Community Edition 2018.3.1 x64 which is available for free...
Read More
BGP session keepalive and hold times
At the beginning of the BGP peering establishment, the BGP neighbors agree on the hold time value (included in OPEN message): the time a peering would be maintained without the reception of a KEEPALIVE...
Read More