Questions tagged [bgp]

BGP is Border Gateway Protocol, used on the internet both inside of and in between networks.

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3answers
650 views

address-family ipv6 on Cisco 3560G

Is anyone aware of an IOS version for the C3560G that supports configuring a neighbor to exchange IPv6 routes? Apparently 12.2(37)SE Advanced IP Services can't do it - as soon as you try to activate ...
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959 views

Leak default route to multiple VRFs while keeping VRFs isolated from each other

I'm working on a configuring stuff on a Cisco Nexus 3k based platform and trying to isolate different things into different VRFs which should not be able to talk to each other. Some of these VRFs ...
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1answer
515 views

Can two networks with the same subnet be connected to the same router in different VRF?

Let's say I have the following four networks: Network A: 10.0.1.0/24 Network B: 10.0.0.0/24 Network C: 10.0.1.0/24 Network D: 10.0.0.0/24 I would like to connect networks A and B together, and do ...
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1answer
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Why does my route-map blackhole some equally specific routes? [closed]

I have a challenging situation. I have two routers, in VIRL, sharing routes via BGP and OSPF I am attempting to remove the "network 0.0.0.0 255.255.255.255 area 0" from my OSPF process. I have tried ...
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1answer
379 views

Connecting eBGP and iBGP routers in Quagga

I am trying to run intra and inter-domain routing using Quagga. I like to announce a prefix from AS7 and I like AS6 receive it and send it to AS2(as shown in the attached topology). I know for intra ...
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2answers
2k views

how can I filter all the BGP routes from one specific AS?

how can I filter all the routes from one AS? I want to filter all routes from AS 6400 towards AS1000, how can I filter whole routes from one AS to another? I do not want to be used as transit AS ...
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1answer
38 views

local pref question

i have a cisco router with 6 bgp peers, 4 bgp peers is from out ip transit's and i am receiving full routing (bgp) table from them. 2 bgp session is over GRE tunnel. and i am receiving 1.1.1.0/24 and ...
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1answer
191 views

How long the EBGP peer convergence time

We are using Anycast, and I plan to implement the "nearest access" by appending myself AS path to impact my peer BGP routers. For example I have two POPs(they are same ip), Pop1 in London and POP2 ...
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1answer
184 views

Explanation of repeated ASN in an AS path from a RouteViews file

From the RouteViews RIB files, I was looking at the snapshot from Nov 06, 2017 at 18:00 UTC. This has to do with this BGP routing misconfiguration -- https://dyn.com/blog/widespread-impact-caused-by-...
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2answers
923 views

VXLAN / EVPN Types

Looking into EVPN and the route types (type 2 and 5) is my understanding correct. In terms of their placement into the relevant forward tables upon the device. EVPN Route Type 2: MAC/IP Advertisement ...
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2answers
799 views

Juniper SR300 maximum BGP routes

I've got a Juniper SRX300 which i'm using to connect to 2 BGP peers. The documentation i've read says this SRX only supports 300,000 BGP routes, so for each peer I created an import policy (based on ...
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2answers
231 views

JunOS Use iBGP route over OSPF route

Hello i have an issue where my Juniper router doesnt advertise BGP 10.255.255.4/32 to a neighbor because in inet.0 it is not issued as the best route root# run show route table inet.0 inet.0: 11 ...
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1answer
217 views

how to change a BGP path in juniper?

How to change the selected BGP route? I show the route 43.242.33.39, there shows 3 GBP paths. but I can not ping the ip(43.242.33.39). and can not traceroute it. how can I do with this?
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1answer
256 views

BGP - Advertise VRF routes

I have a router with a Global Routing Table (GRT), and a VRF. My end goal is to advertise to my eBGP neighbor my VRF routes. I have actually successfully done it by using address-families (ipv4, ...
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2answers
196 views

BGP VPLS - How the destination ip address is mapped?

From RFC and tutorials in the internet I understand that the MPLS cloud acts as a switch and switches traffic between end points in a VPLS. And that VPLS ID along with RD is used to reach the VPLs ...
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5answers
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Should we require a 16-bit ASN?

I am wondering what could be the use case where a 16-bit ASN is needed over a 32-bit ASN at this times. I guess if the user have some older equipment and software 16-bit may be needed. Can some please ...
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1answer
6k views

Smallest IPv6 block advertised?

We've received a /48 allocation from ARIN, and want to advertise smaller blocks from different sites in our organization. I tried advertising a /56 from each site, but ISP is telling me they won't ...
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1answer
4k views

Peering between a private and public ASN (BGP)

I have seen plenty of scenarios where private ASN's are used in a BGP setup and the same for public ASN's - my question is how (or rather is it possible) does BGP work across a network topology that ...
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3answers
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BGP community blackhole

We have created peer with our ISP and my ISP send community to do backhole but how do i configure that and send community string for blackhole traffic. ISP said use 64682:0 community for RTBH, I did ...
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2answers
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bird bgp metric distance

In my lab I have two routers which are connected to different ISPs. They're not directly connected via a wire, but they're connected via a tunnel. Through that tunnel I used to create an iBGP peer ...
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1answer
67 views

Disabling BGP dampening that is enabled for a long time

I have many dampened routes for now. What could possibly happen if I will disable BGP dampening that is previously enabled?
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1answer
2k views

Quagga not announcing external routes over ibgp session

I have a problem when I try to achieve load sharing with bgp. My scenario is http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html#conf3. Only difference to this is ...
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1answer
110 views

Why is the as-path so long?

I got this from bgpmon. Detected new prefix: 121.66.128.0/17 Update time: 2015-11-12 07:18 (UTC) Detected by #peers: 16 Announced by: AS3786 (LG DACOM Corporation) Upstream AS: ...
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2answers
2k views

block route being advertised to SP

I have a network that resembles this CUSTOMER - BT - SPRINT BT - CISCO customer loopback 192.168.10.1 customer loopback1 192.168.1.1 BT loopback 192.168.50.1 CISCO loopback 192.168.100....
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2answers
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Why is ospf to bgp redistribution and simultaneous bgp to ospf redistribution dangerous?

I am referring to this question, where OP apparently fixed his issue by redistributing ospf in bgp and vice-versa on the same router. The user Sebastian warns that this is a dangerous practice. We ...
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1answer
400 views

Dual router, Dual ISP NAT Issue

I have the following topology: 2 Edge Routers - each connecting to a different ISP via eBGP advertising the same PI space EIGRP running between the routers and switches for reachability. On the ...
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1answer
879 views

Cisco BGP synchronization not taking effect

As far as I understand, BGP synchronization is a feature now disabled by default. It only allows iBGP routes to be selected as best (and hence further advertised to other neighbors) if there is a ...
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2answers
1k views

BGP RTBH setup with ISP

I had a discussion a while ago, related how to stop DDoS. Read this first: BGP null route when DDoS? Finally, we talked to the ISP, and it agreed on setting up a BGP trigger so the next time a DDoS ...
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2answers
357 views

BGP loadbalancing: full bgp table vs default route only

I'm trying to achieve this: http://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13762-40.html#conf3. The only difference here is that I am being sent the full BGP routing table. ...
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2answers
494 views

Dynamically generate OSPF/BGP routes based on Internet latency

Scenario Three Offices with 2 ISPs each - utilizing static routing to the ISP. Each office has a VPN and leased point-to-point circuits connecting the offices in a ring. A VPN is also connecting the ...
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1answer
710 views

Is there benefit to iBGP peering between CEs in a BGP dual-homed design?

Two companies wants to exchange some private prefixes (4K prefixes) using eBGP. Each company will have two border routers (with OSPF as IGP, and mutual redistribution & aggregate in eBGP) So, ...
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3answers
654 views

BGP - use prefix on 2 locations

I am currently announcing 8 /24 Subnets over BGP. I am planning to move our servers to a other datacenter, but i want to keep all IPs. Is it possible that i announce the prefixes on 2 locations and ...
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1answer
79 views

Clearing a confusion about sub prefixes in route origin validation (ROA)

According to RIPE's site, a BGP announcements is invalid if: The prefix is announced from an unauthorized AS. The announcement is more specific than is allowed by the maximum length set in ...
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1answer
877 views

ISP HA using GLBP vs BGP

I have a tech startup environment where I'm replacing consumer-grade routers with enterprise-grade. Now, they are asking if we can have dual ISPs to minimize downtime and any disruption. I have: ...
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2answers
217 views

can we do bgp route in cisco 2821 router?

I have a cisco2821 router and it has connected to one Internet service provider. Now i need to buy another one router so that i can have another Internet provider which can help me when one primary ...
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1answer
2k views

Distribute eBGP to OSPF

Im trying to connect 2 AS (each using a separate OSPF) with BGP What i tried so far is: Router TTCore4: router bgp 100 neighbor 10.0.0.34 remote-as 200 network 172.16.1.0 mask 255.255.255.0 ...
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2answers
1k views

BGP peer group type in Junos

In Juniper routers running the Junos operating system, one can set the BGP peer group type either to external or internal: [edit] root@M10i# set groups customer protocols bgp group customer-BGP-group ...
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2answers
807 views

Can I Use BGP as an IGP - Multisite w Redundant Layer 3 MPLS WANs

The requirements are Hundreds of sites. Each has a router and firewall and a switch stack. Layer 3 MPLS WAN with BGP to provider VRF. BGP as an IGP? iBGP Would you distribute a public ASN across all ...
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1answer
1k views

Why use iBGP over eBGP?

Why would you use iBGP over eBGP. i.e why use a single AS with an RR over multiple AS's using eBGP. Is it simply for peering design simplification i.e large amount of devices all peering to a set of ...
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2answers
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Update-source loopback and next-hop-self

I've a question related to BGP configuration. If I'm using the update-source loopback or next-hop-self commands, will they modify the source IP address in the packet? Assume R1 has an eBGP session ...
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1answer
238 views

Using IPv6 for multihome ISP eBGP peering due to IPv4 public /24s no longer available

Problem: I have two routers, and two separate ISPs (two different public ASNs). I wish to accept full BGP routes in order for us to properly set up true reliable ISP failover in a way that allows ...
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1answer
507 views

dual homing WAN circuits BGP

we have the following scenario: MPLS_WAN_provider1 connects to our edge router1 via eBGP MPLS_WAN_provider2 connects to our edge router2 via eBGP Both edge routers are to connect to our LAN. We need ...
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2answers
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Quagga (Zebra) multiprotocol BGP configuration for IP multicast routing

Host A: Eth1 = Multicast incoming from upstream provider OpenVPN_interface_point_A = point to point interface with point B ASN = 100 Host B: OpenVPN_interface_point_B = point to point interface ...
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1answer
162 views

BGP Route Prevention and Slow Connectivity

By default I understand that IBGP should have a full mesh implementation, otherwise route reflectors should be configured while EBGP should be directly connected to establish external neighbor, but ...
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1answer
273 views

BGP - less specific route

I am planning to migrate an /22 Subnet into a other datacenter. Currently i have announced every /24er seperatly. My plan is, that i create a /22 subnet with the AS from the new datacenter on ripe. ...
2
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1answer
787 views

Prioritize redistributed BGP routes over OSPF intra-area

I have a few routers, each controlling a /16, connected together with VPN tunnels. These routers are all in the same OSPF area. Now, I'm also doing BGP with some other routers that I don't control, ...
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2answers
556 views

Gather the BGP data by using TCP connection on port 179

In order to gather the information shared between BGP peers, what port number should be used to connect using TCP (I am using 179, and don't see the connection being established)? Will I be able to ...
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1answer
213 views

BGP Routes - Cisco

Okay the issue i'm having at the moment is i've got a server stack connected to a switch. The switch is then connected to a router. That switch/router combo has been used and tested numerous times. ...
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1answer
146 views

Service Provider inbound routing problems before using communities

As I understand it Service Providers used to use BGPs local preference for manipulating outbound traffic and AS Path for manipulating inbound traffic before they used communities. As the internet grew,...
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1answer
2k views

Download Internet Routing Table

What is the best way to download a snapshot of the Internet's IPv4 routing table? I need check if IP addresses are routable. It needs to function offline, so a looking glass server won't work. I know ...

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