10-17-2006 12:29 AM - edited 03-03-2019 02:22 PM
hi guys,
i dont know if this is possible to advertise just a number of /32 on my provider. we will do some testing on our link and they want me to advertise only 3 ip address's.
tnx
jeff
Solved! Go to Solution.
10-17-2006 03:34 AM
If this is just for testing you could add 3 new loopback interfaces using the /32 and use the commands on the previous post. (dont forget to turn auto-summary off, with no auto-summary) and you are good to go!
Vlad
10-17-2006 01:24 AM
You can advertise /24 or larger subnets (/23 /22 ...), since IPS filter the small subnets updates. If you are sure that your ISP accepts smaller you can do with the aggregate command or with the network command and ip route "IP" "mask" null...
bye
FCS
Please rate me if I helped.
10-17-2006 03:13 AM
If for example, the three IP addr which you want advertised are 192.168.1.1 to 192.168.1.3, then configure the following commands on our ISP-facing BGP router:
router bgp 25
network 192.168.1.1 mask 255.255.255.255
network 192.168.1.2 mask 255.255.255.255
network 192.168.1.3 mask 255.255.255.255
If your eBGP peering with the ISP is working correctly, then these routes will be automatically added to the IP route table of the remote eBGP peer on ISP end.
HTH,
Ahsan M
10-17-2006 03:34 AM
If this is just for testing you could add 3 new loopback interfaces using the /32 and use the commands on the previous post. (dont forget to turn auto-summary off, with no auto-summary) and you are good to go!
Vlad
10-17-2006 04:00 AM
tnx to all.
jeff
10-17-2006 04:16 AM
Hi dear ,
Just make a loopback and advertise that network ip to bgp ...
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a00800945fe.shtml
!
interface Loopback0
ip address 20.20.20.20 255.255.255.255
!
interface Ethernet0/0
ip address 172.16.1.1 255.255.255.0
!
interface Serial8/0
ip address 192.168.16.2 255.255.255.252
!
=================================
example.
router bgp 2
no synchronization
bgp log-neighbor-changes
network 20.20.20.20 mask 255.255.255.255
network 172.16.1.0 mask 255.255.255.0
neighbor 10.10.10.10 remote-as 1
neighbor 10.10.10.10 ebgp-multihop 2
neighbor 10.10.10.10 update-source Loopback0
no auto-summary
!
ip route 10.10.10.0 255.255.255.0 192.168.16.1
==================================
TC / rate if works
prs
03-24-2009 06:38 AM
Hi,
How do we advertise a /32 to one particular neighbor only. Please help.
Thanks in advance
03-24-2009 07:13 AM
Hello,
You can filter your advertisements with prefix-list or route-map
Example:
ip prefix-list PL permit 192.168.0.1/32
router bgp 65001
neighbor 10.0.0.1 remote-as 65002
neighbor 10.0.0.1 prefix-list PL out
Only 192.168.0.1 is advertised to peer 10.0.0.1. Also if you don't want to advertise this prefix to other peers another prefix-list is needed which denies this prefix and permits all others.
ip prefix-list PL1 deny 192.168.0.1/32
ip prefix-list PL1 permit 0.0.0.0/0 le 32
neighbor 10.10.10.2 prefix-list PL1 out
Bye
FCS
03-25-2009 03:07 AM
Hi,
Thanks for the Input. I tried and for some reason I dont get it in the advertised-routes. Here is the config below:
----------------------
router bgp 65555
no synchronization
bgp log-neighbor-changes
neighbor 191.151.81.20 remote-as 1
neighbor 191.151.81.20 soft-reconfiguration inbound
neighbor 191.151.81.20 distribute-list 30 in
neighbor 191.151.81.20 prefix-list test out
no auto-summary
----------------------
sh ip prefix-list
ip prefix-list test: 3 entries
seq 5 permit 192.174.129.2/32
seq 10 permit 192.174.129.253/32
seq 15 permit 192.174.129.254/32
sh ip bgp neighbors 191.151.81.20 advertised-routes
Total number of prefixes 0
Note: I did clear bgp soft out - no change and I did Clear ip bgp * - still nochange.
What am i missing here. Please help.
Thanks in advance
03-25-2009 03:59 AM
Hello,
Do you have routes for your /32 newtorks on the router where BGP runs. You should have exactly the same networks in it, all with /32 mask since no auto-summary.
Bye
FCS
03-25-2009 04:11 AM
Hi,
Thanks for the quick response. I added routes /32 and still no luck. What else to be checked.
Thanks in advance.
03-25-2009 04:55 AM
Could you please change the distribute-list to a prefix-list? what does "show ip bgp" show on your box?
Bye
FCS
03-25-2009 07:02 AM
Hi Jeff,
it's most likely that your ISP block your /32 prefixes, because the most internet service provider protect the internet against prefixes which are bigger than /24.
Michael
03-27-2009 02:47 AM
Thanks mate. It was the case. I got it working after they allowed it.
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