Need Help In BGP Design-Multihomed

[Mitesh Manwatkar]

Hi,

I have a public ip pool for my servers to be on internet and I have a internet connectivity from 2 ISPs.

I want to achieve following:

1.I want to advertise my public block on the internet.

2.I want internet connectivity from both isp but in primary/secondary manner.

3.I dont want to receive bgp routing table from both isp.

Kindly help with the config required on my end

[mvsheik123]

Hi,

Couple of questions..

1.Your ISP supports BGP?

2. You have /24 subnet? If not check with your ISPs first as most ISPs does not advertise subnets lless than /24.

3.Try to get your own Autonomous system number (AS#) from ARIN. If not, some ISPs work with private AS# as well.

Check the below links for different scenarios..

http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/23675-27.html

http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html

hth

MS

[Mitesh Manwatkar]

Hi,

I have a /26 subnet with private AS# and both ISP support bgp.

I want to advertise my subnet to the world so that anyone can reach my servers on internet.

However i don't want to receive bgp routing table from my ISP but want my users to get internet.

How to achieve this?

Regards

[Reza Sharifi]

Hi,

Advertise your /26 in your BGP peering with the ISPs and have them send you a default route.

This way, you only have a default route in your routing table pointing to the providers.

HTH

[paul driver]

Hello

You can also  make sure of this by only allowing a default route into your network

ip prefix-list default-route permit 0.0.0.0/0
ip prefix-list default-route deny 0.0.0.0/0 le 32
ip as=path access-list 1 permit ^$

router bgp xxx
Network x.x.x.x 255.255.255.192 ( your 26 advertised subnet)
neighbour (isp1 next hop) prefix-list default-route in
neighbour (isp2 next hop) prefix-list default-route in
neighbour (isp1 next hop) filter-list 1 out ( prohibit transit routes Between isp1 and isp2
neighbour (isp2 next hop) filter-list 1 out ( prohibit transit routes between isp2 and isp1)

res

Paul

[Mitesh Manwatkar]

Thanx...jst for knowledge purpose i wud like 2 no dat how isp wud send me default route...what commands will he use?

[Reza Sharifi]

The ISP will advertise a default route using the BGP peering with you. You then follow that default route to get to Internet

HTH

[Mitesh Manwatkar]

Thanx 4 d sharing the links....it solved my queries a lot....

Cheers....!!!!!!!!

[paul driver]

Hello

please rate any posts that have been helpfull

thanks