Configure BGP
Configure BGP
https://www.experts-exchange.com/questions/29010316/Public-DNS-Vs-BGP.html
following the Thread on the above link, When I purchase Public IP addresse(s), and register the IP addresse(S) with a Public DNS, then how do I configure my router for BGP so that customers will chose ISP1 as most preferred to get to that public IP address and use ISP2 as less preferred
Thank you
https://www.experts-exchange.com/questions/29010316/Public-DNS-Vs-BGP.html
following the Thread on the above link, When I purchase Public IP addresse(s), and register the IP addresse(S) with a Public DNS, then how do I configure my router for BGP so that customers will chose ISP1 as most preferred to get to that public IP address and use ISP2 as less preferred
Thank you
Last Comment
Jan Bacher
What router manufacturer?
ASKER
That 's Cisco Router
This should work:
##########################
ip prefix-list ANNOUNCE seq 5 192.168.0.0/24
ip prefix-list ANNOUNCE seq 5 192.168.2.0/23 le 24
route-map LOCALPREF permit 10
set local-preference 500
route-map DEPREFER permit 10
match ip address ANNOUNCE
set as-path prepend 65535 65535 65535
router bgp 65535
neighbor 10.0.0.1 description Primary ISP
neighbor 10.0.0.1 route-map in LOCALPREF
neighbor 10.0.0.1 prefix-list ANNOUNCE out
neighbor 172.16.2.1 description Backup ISP
neighbor 172.16.2.1 route-map DEPREFER out
##########################
ip prefix-list ANNOUNCE seq 5 192.168.0.0/24
ip prefix-list ANNOUNCE seq 5 192.168.2.0/23 le 24
route-map LOCALPREF permit 10
set local-preference 500
route-map DEPREFER permit 10
match ip address ANNOUNCE
set as-path prepend 65535 65535 65535
router bgp 65535
neighbor 10.0.0.1 description Primary ISP
neighbor 10.0.0.1 route-map in LOCALPREF
neighbor 10.0.0.1 prefix-list ANNOUNCE out
neighbor 172.16.2.1 description Backup ISP
neighbor 172.16.2.1 route-map DEPREFER out
ASKER
Thanks Jan Springer,
for Education purposes, can you please comment below each line, just to explain what each line is meant for ?
for Education purposes, can you please comment below each line, just to explain what each line is meant for ?
The prefix list defines those subnets that you are announcing to your upstream.
The LOCALPREF route-map assigns a higher local preference for outgoing traffic to your preferred provider.
The DEPREFER route-map prepends your ASN to create a longer and less preferred path.
The LOCALPREF route-map assigns a higher local preference for outgoing traffic to your preferred provider.
The DEPREFER route-map prepends your ASN to create a longer and less preferred path.
ASKER
in your example
192.168.0.0/24 is the Public IP that is registered on the public DNS ?
the same applies to this one 192.168.2.0/23 le 24?
192.168.0.0/24 is the Public IP that is registered on the public DNS ?
the same applies to this one 192.168.2.0/23 le 24?
No, that's the subnet that's assigned to you either by one of your providers or your RIR.
IPs out of that subnet could/would be defined in DNS.
"le 24" means allow me to announce this subnet as one /23 or two /24s.
IPs out of that subnet could/would be defined in DNS.
"le 24" means allow me to announce this subnet as one /23 or two /24s.
ASKER
Ok Thanks Jan...
What is the key word
neighbor 10.0.0.1 prefix-list ANNOUNCE out
and
neighbor 172.16.2.1 route-map DEPREFER out
Why not "IN", since customer will try to get in ?
What is the key word
OUTmeaning in :
neighbor 10.0.0.1 prefix-list ANNOUNCE out
and
neighbor 172.16.2.1 route-map DEPREFER out
Why not "IN", since customer will try to get in ?
I want to announce these prefixes going OUT to my neighbor.
How I want to traffic engineer data coming IN to me.
The "why" has to do with logic and how the people that wrote the RFCs determined.
How I want to traffic engineer data coming IN to me.
The "why" has to do with logic and how the people that wrote the RFCs determined.
ASKER
I thought since these subnets are already out on the Public DNS
192.168.0.0/24
192.168.2.0/23 le 24
customers will use them to get in
192.168.0.0/24
192.168.2.0/23 le 24
customers will use them to get in
ASKER
Jan Springer,
probably if you can comment each line..That might help me understand better the "Morse Code"
probably if you can comment each line..That might help me understand better the "Morse Code"
The purpose of using BGP is to tell your router how you want to reach the outside world and how you want the outside world to reach you.
Again. You are confusing BGP and DNS.
Again. You are confusing BGP and DNS.
ASKER
In your example what do these IP addresses represent ?
192.168.0.0/24
192.168.2.0/23
10.0.0.1
10.0.0.1
10.0.0.1
172.16.2.1
172.16.2.1
192.168.0.0/24
192.168.2.0/23
10.0.0.1
10.0.0.1
10.0.0.1
172.16.2.1
172.16.2.1
ASKER
Ok , just to confirm the way they have explained it to me:
My company will have Public IP addresses for my web servers x.x.x.x , y.y.y.y , these addresses Registered in DNS.
I will advertise those IP Subnets to ISP-A and ISP-B , then on my edge router I can configure, for instance if a Customer needs access x.x.x.x network then they can come through ISP-A if they need to access y.y.y.y network then they can come through ISP-B
My company will have Public IP addresses for my web servers x.x.x.x , y.y.y.y , these addresses Registered in DNS.
I will advertise those IP Subnets to ISP-A and ISP-B , then on my edge router I can configure, for instance if a Customer needs access x.x.x.x network then they can come through ISP-A if they need to access y.y.y.y network then they can come through ISP-B
No.
If you can advertise address space via BGP, then you have a /24 or larger. Those are the IPs that you put on your server and configure in DNS.
The path taken by your customers to reach you will be determined by your traffic engineering (localpref, etc) and their provider traffic engineering.
And it looks like this:
SomeRemoteIPs => Internet => ProviderA \
=> MyCompanyRouter => Servers
OtherRemoteIPs => Internet => ProviderB /
If you can advertise address space via BGP, then you have a /24 or larger. Those are the IPs that you put on your server and configure in DNS.
The path taken by your customers to reach you will be determined by your traffic engineering (localpref, etc) and their provider traffic engineering.
And it looks like this:
SomeRemoteIPs => Internet => ProviderA \
=> MyCompanyRouter => Servers
OtherRemoteIPs => Internet => ProviderB /
ASKER
MyCompany is my Router where BGP is configured.. it will advertize to ISP-A and ISP-B the purchased IP subnets.
Public DNS will have Ip addresses of my web servers..
The path that will be taken by my customers to reach my web servers will be determined by the configuration of BGP on Mycompany router (as you stated for instance using Local Preference attribute)
Public DNS will have Ip addresses of my web servers..
The path that will be taken by my customers to reach my web servers will be determined by the configuration of BGP on Mycompany router (as you stated for instance using Local Preference attribute)
ASKER
the IP addresses I put on public DNS , will be within the subnets I advertize through BGP
ASKER
Correct ?
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ASKER
I see what you are saying ...
Was just example in case you purchased 2 or more IP ranges for 2 or more different sites
Was just example in case you purchased 2 or more IP ranges for 2 or more different sites
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ASKER
Thank you Jan Springer
Routers
A router is a networking device that forwards data packets between computer networks. Routers perform the "traffic directing" functions on the Internet. The most familiar type of routers are home and small office cable or DSL routers that simply pass data, such as web pages, email, IM, and videos between computers and the Internet. More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, use of software-based routers has grown increasingly common.
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