BGP - aggregate-address default route

BGP - using peer-groups with multiple outbound policies


Default routes are used by [routing](/routing) devices to forward packets to destination networks that are not specifically defined in entries within the [routing table](/routing-table).

There are a couple of ways to configure a router running [BGP](/bgp) to advertise a default route to its BGP peers.

## Network Command

Configure a static route to the 0.0.0.0/0 network pointing to the null 0 interface by issuing the `ip route 0.0.0.0 0.0.0.0 null0` command.  Then use the `network 0.0.0.0` command to inject the route into BGP.

## Default-Originate

Add a default route to the null0 interface with `ip route 0.0.0.0 0.0.0.0 null0` and then use the `neighbor x.x.x.x default-originate` command to advertise the default route.

## Links

https://networklessons.com/bgp/how-to-advertise-networks-in-bgp/

BGP advertising a default route

BGP - using private ASNs with private IPs

BGP - using public IPs with private ASes

BGP - why is eBGP preferred over iBGP

BGP 4-Byte AS Number - Asdot notation

BGP 4-Byte AS Number - Asdot plus notation

BGP 4-Byte AS Number - Asplain notation

BGP 4-byte ASN Backward Compatibility

BGP AS Path Filtering and Manipulation

BGP AS Path

BGP AS number notation

BGP AS-Override Risks

BGP AS_PATH when using aggregate-address

BGP AS_SET and AS_CONFED_SET Deprecated

BGP AS_TRANS

BGP Advertised Routes and Outbound Policy Application

BGP Advertising a prefix

BGP Advertising a route using the Null0 exit interface

BGP Asymmetric routing when using ASA with AWS

BGP Attributes - route map direction

BGP Authentication

BGP Auto-Summary Best Practices

BGP Cluster ID

BGP Confederation peerings

BGP Confederations

BGP Default local preference and its appearance in the BGP table

BGP Equal Cost Multipath AS_Path Attribute

BGP Equal cost multipath configuration syntax

BGP Equal cost multipath

BGP Extended Community

BGP ISPs prefixes advertised to enterprise edge routers

BGP Influence incoming traffic

BGP Load balancing

BGP MD5 Authentication

BGP Maximum Prefix Feature

BGP Maximum message size

BGP Origin AS Validation

BGP Originator ID

BGP PIC and its Relationship with BGP Attributes

BGP Path Selection Oldest Path

BGP RIB failure Administrative Distance

BGP RIB failure

BGP Routing Table Entry without Exit Interface

BGP Site of Origin (SoO) Community

BGP Standard Community

BGP Table Origin Code

BGP Update Groups

BGP Update Total Path Attribute Length field

BGP active and passive peers

BGP advertises only the best path by default

BGP aggregate-address

BGP and route tagging

BGP applying route maps to prefixes

BGP communities

BGP community propagation

BGP community types

BGP configuring authentication on an established BGP session

BGP dmzlink-bw feature

BGP eBGP next hop optimization

BGP hold timer

BGP how MED attribute is compared

BGP influence Outgoing Traffic

BGP installing a BGP-learned route into the routing table

BGP internal vs external

BGP multihop vs disable-connected-check

BGP neighbor activate command

BGP neighbor-group

BGP paths indicated in the show ip bgp command

BGP peer templates

BGP peering redundancy using loopbacks

BGP private AS numbers

BGP regular expressions - use of 4-Byte ASNs

BGP regular expressions - use of backslash for confederations

BGP route dampening penalty half-life

BGP route refresh capability annoucement

BGP soft reconfiguration on Cisco ASA

BGP sub autonomous system

BGP table status codes

BGP traffic engineering

BGP using next-hop-self with a route reflector

BGP weight attribute default value

BGP when to use next-hop-self

BGP which address is used as the next hop

BGP why do we need an IGP for BGP to work

BGP why route dampening is obsolete

Best practice - concerning undebug all

Best practice - prevent connectivity loss of remote device

Bidirectional Forwarding Detection (BFD)

Broadcast Domain Borders

Broadcast MAC address

Broadcast traffic

CBC-MAC

CBWFQ and shaping

CCNP SCOR exam topics

CDP - best practices

CDP versions messages timers

CEF - Operation within a chassis switch

CEF Load Balancing Algorithm

CISCO ASA IKEv2 hub and spoke

BGP advertising a default route

Network Command

Default-Originate

Links

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