Routing Flashcards
Routed Protocols:
o Routed protocols are the actual data that is transferred from router to router.
o Examples of routed protocols are Internet Protocol (IP) such as IPV4 and IPV6.
o Routed Protocol is used to send user data from one network to another network.
o Routed Protocol carries user traffic such as e-mails, file transfers, web traffic etc.
o Used between routers to direct user traffic, it is also called network protocols.
o That are signs at intersections that point to nearby cities, giving mileage to each.
Routing Protocols:
o Routing protocols are used by routers to exchange information about known networks.
o Routers will initially only know the existence of directly connected networks.
o With the use of routing protocols routers communicate with & learn from other routers.
o Routing protocols are used to distribute routing information across routers on a network.
o Routing protocol is Google Maps: It tells you the best way to get where you want to go.
Connected:
o Connected routes are IP Subnet belonging to Firewall interfaces itself.
o All interfaces configured in the Firewall will belong to this category.
o Connected are the most commonly routes used for Redistribution.
o any /32 interface configured on Firewall are not considered Connected.
o Any /32 interface is consider Host, and therefore cannot be redistributed.
Static Routing
o Static Routing administrator manually inputs all routing table information.
o A static route is a route that is created manually by a network administrator.
o Router’s routing table entries are populated manually by network administrator.
o Static route tells the network devices about exact location for the routes.
o Static routes are typically and can only be used in smaller networks.
o Configure static routes between devices to allow data transfer between devices.
o Major advantages of static routing are reduced routing protocol router overhead.
o Another advantage of static routing it reduced routing protocol network traffic.
o Disadvantages of static routing are network changes require manual reconfiguration.
o Easy to Configure, High Secure, Use Low Resources, Bandwidth & in small network.
o In PA Static Routing does not require Advanced Knowledge to configure them.
o By default, in PA Firewall the static routes have an Administrative Distance of 10
Default Routing:
o A Default Route also known as the gateway of last resort is a special type of static route.
o This method where all routers are configured to send all packets towards single device.
o Default Route is network route used by device when there is no other known route exists.
o All the IP datagrams with unknown destination address are sent to the default route.
Dynamic Routing:
o Dynamic routing protocols can dynamically respond to changes in the network.
o Routing protocol is configured on each device & device learn about both each other.
o Dynamic routing table is created, maintained and updates by routing protocol.
o Examples of Dynamic routing protocols includes RIPv2, OSPFV3 and OSPF and BGP.
o Dynamic routing protocols share routing updates with neighbors and find best path.
o Dynamically choose a different route if a link goes also updates are dynamically.
o Also, Dynamic Protocols has the ability to load balance between multiple links.
o Dynamic Routing protocols put additional load on devices CPU and RAM.
o The choice of the best route is on the hands of the Dynamic Routing Protocol.
Administrative Distance:
o Administrative distance is the feature that routers use to select best path.
o Administrative Distance (AD) defines the reliability of a routing protocol.
o The administrative Distance (AD) number is start from 0 and end on 240.
o AD has only local significance and is not advertised in routing updates.
o The smaller Administrative Distance value, the more reliable the protocol.
o In multiple routing protocols, AD is used to determine trustable protocol.
o Routing Protocol with lowest Administrative Distance wins put in routing table.
o Administrative distance of 255 will cause the router to Disbelieve route entirely.
o AD value of 255 router disbelieve & will be excluded from route selection process.
o AD are set from Network > Virtual Routers > vr_name > General screen & are applicable
Route Metric:
o The Route Metric is similar to AD in helping to select or predict the best route.
o However, route metrics are only applicable within a single routing protocol.
o Route Metric are not used when forwarding traffic through multiple protocols.
o To forwarding traffic through multiple protocols Administrative Distance is used.
o Route Metric on Palo Alto Firewalls can be set to determine the route selection.
o The Route Metric is used when there are multiple paths to the same destination.
o In Palo Alto Network Firewall Lower metric values are preferred over higher values
RIB:
o RIB is a PA Firewall term which is stand for Routing Information Base.
o All routes learned are first place in the Routing Information Base (RIB).
o Show routing route, command will display the RIB table from the Firewall.
o All the routes that are “active” are marked with an “A” in the flags column
FIB:
o FIB is a PA Firewall term which is stand for Forwarding Information Base.
o Best route obtained through protocols are used to populate the firewall’s FIB.
o Show routing fib, command will display the FIB table from the PA Firewall.
o Firewall chooses the best route toward destination network to place in the FIB.
Redistribute:
o Redistribute Rule allows to “Redistribute” route from one protocol into another.
o Redistribution allows devices to share routes info among routing protocols.
o Redistribution profiles are only way to exchange routing info between protocols.
o Palo Alto Firewalls provide flexible, profile-based approach for route redistribution.
o PA Firewall also provide filtering between protocols, static routes, connected & hosts.
o In PA Firewall Without redistribution profiles, each protocol functions on its own.
o Does not exchange any route info with other protocols running on same virtual router.
o Redistribute static route into dynamic routing protocol like OSPF is common use case
