01-08-2019 12:47 AM
May I know which is the cmd to advertise loopback ip?
Because there is no something like that in my router config. But when i show ip bgp , the loopback ip is indeed advertised.
R1(config)#router bgp 1 R1(config-router)#network 11.11.11.0 mask 255.255.255.0
router bgp 64478
bgp router-id 200.31.2.7
bgp log-neighbor-changes
neighbor 10.20.2.1 remote-as 67845
neighbor 10.20.2.1 timers 3 22
neighbor 209.16.4.5 remote-as 3423
neighbor 209.16.4.5 timers 4 22
!
address-family ipv4
redistribute connected
redistribute static
neighbor 10.20.2.1 activate
neighbor 10.20.2.1 next-hop-self
neighbor 209.16.4.5 activate
neighbor 209.16.4.5 soft-reconfiguration inbound
neighbor 209.16.4.5 filter-list 15 out
exit-address-family
Solved! Go to Solution.
01-08-2019 04:02 AM
BGP has three ways to advertise a route but based on your question i will highlight only the two that are relevant.
network
commandredistribute
commandThe network
command requires you to explicitly specify which networks should be advertised into BGP. Where as the redistribute
command might inadvertently advertise networks into BGP that you did not explicitly select (aka, using redistribute connected
and later adding an loopback interface for testing that you did not mean to get advertise).
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01-08-2019 01:06 AM
You can either use the redistribute command which already seems to be present or the network statement under the bgp process,
network 1.1.1.1 mask 255.255.255.255
Rob
01-08-2019 01:18 AM
is the loopback advertised due to the command "redistribute connected"?
01-08-2019 03:41 AM - edited 01-08-2019 03:47 AM
What is the loopback IP ?
As you are not advertising any subnets in your BGP configuration then it looks like it is the redistribute connected that is responsible for the advertising.
Jon
01-08-2019 01:19 AM
is the loopback advertised due to the command "redistribute connected"?
01-08-2019 04:02 AM
BGP has three ways to advertise a route but based on your question i will highlight only the two that are relevant.
network
commandredistribute
commandThe network
command requires you to explicitly specify which networks should be advertised into BGP. Where as the redistribute
command might inadvertently advertise networks into BGP that you did not explicitly select (aka, using redistribute connected
and later adding an loopback interface for testing that you did not mean to get advertise).
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01-08-2019 07:32 PM
do you mean that redistribute connected also includes loopback ip?
01-09-2019 12:20 AM
Yes, it does.
Jon
01-09-2019 03:19 AM
It means that all IP address associated with any interface including loopback ( directly connected interfaces) will be redistributed into bgp.
i.e BGP will will add these associated loopback networks into its routing table and advertise them to its neighbors.
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