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Questions tagged [bgp]

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

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How do you specify BGP Authentication Key when using Verizon's Secure Cloud Interconnect?

I am trying to establish a Direct Connect Link using Verizon's Secure Cloud Interconnect service. I have established the connection in the Dynamic Network Manager on the Verizon side and the VIFs ...
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In one organization having two ISP which configured on fortigate firewall ? How can we do the failover for internet?

Organisation don't have AS number .As of now we are doing manually route for any ISP at a time. when default Internet link is go down that time making second link enable on firewall. I saw the some ...
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3answers
40 views

How is traffic forwarded though IXPs if route servers do not forward any traffic

while i was studying about IXP route-servers, i read that they do not forward any traffic. I get that a route server is a "control plane" entity and it is used for easier bgp peering. However, i ...
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1answer
45 views

Setting local preference in BGP

I am trying to set the local preference for this configuration To make a route from R1 to R4 via R3. That's how i configure R3 R3#conf term Enter configuration commands, one per line. End with ...
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1answer
30 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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1answer
35 views

Bad mask for loopback interface

I am trying to implement BGP session. I was given this table. When I try to configure loopbacks the first loopback works in the proper way R1(config)#interface loopback 0 R1(config-if)#ip *Mar 1 ...
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0answers
28 views

How to manipulate as-path

I have a situation where i'm forced to provide transit for a certain prefix over a customer CE router RTR3 between two VRFs. The RTR3 in question is a Cisco 6500. ****VRF1(customer1)@PE1----- * ...
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2answers
49 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 ...
2
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1answer
44 views

Use case for two BGP ASNs?

I’m new to BGP and have a relatively simple question, or so I think it is for you BGP veterans. I would like to build two new seperate edge networks at my company; one for production services and ...
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1answer
23 views

All routes about a IP in my Router AS-PATH last AS number is Idle

I can not ping the IP 202.137.151.185 from my router. and in my router I show a IP's route, there gets the following information: admin@EE-MX-RE1# run show route 202.137.151.185 ...
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0answers
24 views

There is no “update-source” param in the BGP neighbor

In the tutorial, there are BGP's neighbor update-source. but when I test the Router, there is no that command. R1(config-router)#neighbor 2.2.2.2 ? next-hop-self Disable the next hop ...
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3answers
1k views

Why is the BGP base on TCP 1027 rather than 179?

Why is the BGP foreign address port 1027? I use BGP to connect Router1 and Router2, but when I show the TCP progress: Router1>show tcp brief TCB Local Address Foreign Address ...
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1answer
57 views

Why do we need MPLS when implementing L2/L3 VPNs?

Yes, I know that MPLS doesn't care about L3 and higher levels and it is one of its features. But I do not really understand its role in L2/L3 VPNs. L2VPN - we are building xconnects to PE's AC. Why ...
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19 views

BGP - Just learning. Does the ISP router config need to specify your AS number

I am migrating two firewall into one, both firewalls run BGP and have different AS numbers. On the new firewall I only have one AS number - Is the secondary ISP required to change any configuration ...
2
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1answer
17 views

How can I see where BGP is advertising a given prefix? (Junos)

I'm working in a complex BGP environment on Juniper MX480s. We have many peers in various routing instances advertising prefixes to us, and then we advertise a subset of those prefixes to a subset of ...
5
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0answers
97 views

Cisco BGP Graceful Restart behavior

In our environment we generally have ASR-1000X-2s everywhere peering via iBGP/eBGP. These routers have no redundant RPs, hence cannot keep forwarding traffic while the router reboots or crashes. As ...
2
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1answer
39 views

Does the iBGP belong IGP?

We know the iBGP in the AS can transmit the BGP data, it running in the AS, is it belong IGP?
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2answers
90 views

Issues with Juniper MX-series iBGP routes

I have a simple setup: 2x Juniper MX-Series routers each having one uplink to a transit provider iBGP session between both routers (point-to-point) For testing purposes I've disabled the uplink from ...
5
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1answer
55 views

PP BGP Load Balancing with JUNOS

So we've got a couple of BGP upstream providers, whom both are providing us with their full internet routing tables. What we are now wanting to do, is utilize both providers, rather than just one ...
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0answers
19 views

How does BGP decide which prefix to advertise out of the prefixes in the routing table? [duplicate]

The ip routing table shows that I have 4 routes to reach 0.0.0.0/0. #show ip route 0.0.0.0/0 0.0.0.0/0, ubest/mbest: 4/0 *via x.x.16.6, [20/0], 2d, bgp-64500, external, tag 64500 *via x.x.17.4, [20/0]...
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1answer
81 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 ...
3
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1answer
140 views

Config BGP policy for limit ISP path in Juniper MX 480 Router

Now we have a source IP14.135.4.0/24, we are involved in 5 different ISP, such as A, B, C, D, E. Now we want to access 14.135.4.0/24 not through the path of ISP B and ISP D, but through the other ...
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1answer
35 views

Routing an owned /24 IPv4 block to a single server [closed]

How would one go about routing a recently-purchased /24 block of IPv4's to a single server? The server is colocated in Zare.com, and the BGP session is already set up and announced.
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1answer
99 views

How to find a AS-SET of an asn?

How can we find the as-set of asn? For Example I have the asn:32934. I want the as-set?
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2answers
91 views

BGP with x2 sessions and x2 L3 VLANs - Please Explain

I am learning about Cisco BGP networking now and came across an interesting situation. In my examples, there was one which suggested that two VLANs were configured on Layer 3 in order to run two BGP ...
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1answer
71 views

How can I reduce latency to Australia from another country? [closed]

I often do a lot of work from the UK to destination networks in Australia be it voice calls or something more benign like gaming. Both of which work best with the lowest RTT possible. On average the ...
0
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1answer
59 views

Can i implement BGP flowspec

This question is for general information about BGP flowspec, Can i implement BGP flowspec to stop DDoS? RTBH isn't what we want because it blackholing all traffic, we want RTBH at Layer 4 level where ...
0
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1answer
33 views

Strange BGP routing issue between two public routers. Not able to see subnets

Having a strange issue can't seem to figure out what's happening. I got 2 routers running BGP. Router A is advertising 23.128.128.0/24 subnet and Router B is advertising 23.128.129.0/24. Routing is ...
4
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1answer
86 views

JunOS iBGP session not establishing

I have a test environment set up with two Juniper vSRX instances and a L2 network trunked between them and can reach each other on the IP addresses I'm trying to peer them on. vSRX 1 has an external ...
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2answers
117 views

Can we have multiple AS number in the same router?

Is it possible to have multiple AS number in the same router? Example: Routing-Instance A for AS100 and Routing-Instance B for AS200 ? Please share me some example or configuration.
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2answers
95 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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2answers
53 views

Using a Public AS Number Internally

We have BGP between our network and our customers networks and so far each connection uses private AS numbers (on our end we use a different AS number for each connection) We recently got a public AS ...
1
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1answer
59 views

how to select the most optimized BGP Anycast combination with BGP as-path prepending

The question as following: Suppose I have 3 POP (Points of Presence) points, they have the same IP address and located at different countries, such as: USA, Japan, England. The three countries serve ...
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2answers
71 views

BGP new subnet announcement

I have above scenario where I got public IP subnet got from ISP 74.100.100.0/23 and i have configured eBGP and iBGP as you can see in diagram, I have configured those Public IP in HSRP my LAN side. ...
3
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0answers
51 views

mp_reach_nlri bgp Update with 4-byte Community ASN?

I am BGP peering with a Juniper OS router. When starting the connection, my system advertises 4-byte ASN capability, which is accepted by the Juniper router: Jul 28 00:33:00.664202 BGP RECV 4 Byte ...
5
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1answer
156 views

Max AS path to accept from peer?

I heard that once AS receives a BGP update that is longer than 50, it will be dropped. Is this true or just happens with some ISPs specifying that policy? I cannot find any evidence or official ...
3
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1answer
142 views

ISP lab GNS3 - BGP route exchange

I'm trying to develop an understanding of the WAN/ISPs. Eventually I'll build up to MPLS, but for now I'm trying to lab up a notional, basic ISP: R1, R2, and R4 are PE routers. They've successfully ...
3
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2answers
157 views

Thousands of open BGP ports at some organisations - Is there a reason for this?

I hope this is the right place to ask this, but I've been browsing Shodan in the hope of gaining some insight as to how many services my organisation has that are externally accessible so I can work ...
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2answers
96 views

BGP source base routing question

This question is little convoluted to explain but i will try my best, I have following scenario. I have one ISP and i am getting 2x40G drops which you can see in diagram Link-A and Link-B (Both ...
3
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1answer
304 views

How to announce network to specific neighbor peer in BGP

I have following scenario where i already have 10G (A - BLUE Link) connectivity from ISP on SW1 and SW2 for redendency and i have configured eBGP and iBGP, Everything is good at this point, Now my ...
4
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1answer
273 views

AWS direct connect BGP issue

This is out current setup and everything working great!!! here, now i want backup link for AWS so i have request for one more secondary link and terminated on Cisco ASA on Port-channel1.8 interface. ...
0
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1answer
115 views

Why Connected Routes are not shown as RIB failure in BGP Table?

I know that “RIB failure” in a “show ip bgp” output indicates that a route offered to the RIB by BGP has not been accepted. But why then the connected Routes that are being advertised by the BGP ...
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1answer
107 views

Redundant internet connection with multiple lte modems

Hy i wan't to build a Redundant Internet Gateway to use multiple usb LTE Modems with diffrent SIM Cards. The goal of this is to install it on a Boat in a medium sized lake. The boat route is along the ...
0
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1answer
29 views

Edit BGP on IOS XE3

i need to edit my BGP Running , and add more Neighbor but when try this FiberISP-Cisco(config)#router bgp 203725 BGP is already running; AS is 203735 FiberISP-Cisco(config)# how to edit and add ...
2
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1answer
66 views

Why does source RTBH need uRPF

I'm trying to understand why source-address RTBH needs to be coupled with configuring uRPF on the edge ports. I've read RFC5635 and other vendor papers on this topics but I can't figure out the ...
2
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1answer
39 views

Traffic Destined to X Should Bypass a Certain AS Y

Let's say you do not want the traffic destined to your /8 prefix to traverse AS Y. How would you modify your BGP configuration to do that? Thank you for your time
4
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1answer
94 views

In what conditions an AS is triggered to broadcast BGP withdrawal message?

I'm not very familiar with the mechanism of withdrawing BGP announcements so welcome any comment. Assuming AS1 broadcasted to AS2 an AS path to its prefix and AS2 forwarded that announcement to the ...
0
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1answer
139 views

Question about BGP peering with your ISP

In you case you want to get rid of the static default route and you want to peer with your single ISP, do you need to announce any routes for your side ? I have the below config, is it enough for ...
2
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1answer
68 views

What is the preferred way to prevent a particular subnet from being sent to one ASN

I have the following network. I want to prevent Subnet 2, S2, from being routed outbound of ISPA (preferring ISPC is also acceptable). None of my ISPs use BGP communities. Given that this is a live ...
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3answers
104 views

Can SDN controllers inject or delete routes in a router?

I have seen that some SDN controllers implement a BGP plugin in their architecture (for instance, Opendaylight). But, since controllers do not sent or route packets, I wonder how and if they can ...