Questions tagged [ospf]

For questions about OSPF. Open Shortest Path First (OSPF) is a link-state routing protocol for Internet Protocol (IP) networks.

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Does OSPF acknowledge DBD packets with an LSAck?

I don't see any LSAck for DBDs being sent out in this sample pcap:- https://www.cloudshark.org/captures/e7dbbc860456 Does OSPF really send LSAck upon reception of DBD packets ?
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Ospf multicasting with two different group

Suppose I have one ospf network where two multicast group exists. And some routers is ospf which belongs to one group or multiple group (Like: routers E, H) and router is layer3 router (Like: ...
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CCNA | OSPF | What differences can exist between two processes of a single routing protocol?

It is my understanding that a process is a specific-instance of a routing protocol. The process-id is a symbolic representation of a unique instance of that RP within a router. If that's the case, ...
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CCNA / OSPF / Area / Alternative Definition

Can another definition for an OPSF area be: A multicast domain within a larger autonomous system that is primarily subject to a single LSDB (topology database)? //edit I'll modify my definition soon.
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Why can't I ping from a pc in one OSPF area to a pc in another OSPF area after configuring each neighbouring network?

So I have an exercise with this topology: I have configured all the OSPF networks on each router and I made every g0/0 interface (except for the ABR in the middle) a passive interface. However, I ...
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OSPF Theory Question | Area Design

I know there are many assumptions to this question but: Would it be possible to simultaneously configure all area x routers through something like SNMP for the purpose of merging with another area? If ...
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OSPF Theory Question | Topology Changes | LSU Flooding

Could you create a script on an ospf router that enable/disables interfaces randomly, and faster than time neighbor routers update their LSDBs, making a network that's constantly flooded with LSU ...
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Trying To connect Router4 to internet

In the picture, I have a part of my topology. The concept is that I am trying to configure OSPF in my network. Internet is a nat cloud module. The routers are all iosv routers. ISP 1 has the following ...
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Routing for same subnets in remote sites

Is it possible to have interVLAN routing with router on a stick topology, but with remote sites communicating via OSPF? In the diagram below, I can ping PC1 from PC0. What I want is to ping PC2 and ...
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Why does redistributing ospf in rip change the path of all routers on the rip network that are not directly connected to the router that redistributed

I have three routers connected to each other. Each has a subnet that it uses (eigrp, ospf, rip) as shown in the figure I managed to redistribute EIGRP and OSPF, this works perfect. But when I try to ...
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What does the OSPF RFC mean when it says "The master sends the first Database Description Packet"? [duplicate]

I'm trying to reconcile what I've read about the OSPF Master/Slave process, with what the RFC says, with what I'm seeing on the wire. Everything I've read implies the Master starts the LSA exchange by ...
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Does vIPtela vEdge router (Cisco ISR1100) support OSPF Link Local Sharing (OSPF LLS)?

I am using Cisco ISR1100. This is the system information in detail. Viptela (tm) vedge Operating System Software Copyright (c) 2013-2022 by Viptela, Inc. Controller Compatibility: Version: 19.2.3 ...
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How to view or change OSPF LSA max-age time in Cisco IOS?

Is there any way of viewing or changing OSPF LSA Max-Age time in Cisco IOS?
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Designing Workaround for Missing IPv6 Support (OSPF or BGP)

We have a pair of Ruckus (Brocade) ICX 7750s that we use as our core routers. They currently handle a BGP connection with our ISP and then use OSPF for internal routes. Our ISP is finally going to ...
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Passive interface default - issue

I was trying to configure ospf router, I have a router connected to FW in G1/0/10 and mpls router connected g1/0/1, when i typed passive interface default in the ospf router i lost all connectivity ...
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Meaning of import or export in Juniper routing policies

What exactly is happening to the junos ospf protocol and junos routing instance when one executes these commands? set policy-options policy-statement POLICY-STATIC term TERM-STATIC from protocol ...
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OSPF and RIPv2 behaviour with route through switch

I have 2 questions, both relates to routing protocols. How route/path looks like when there is L2 switch inside path. I mean with turned on either RIPv2 or OSPF. To clarify I must say there are 2 ...
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OSPFv3 Authentication IPSEC SPI/Logging issues - Can you filter out logs?

I'm running into a problem with our Cisco ASR-1002HX and ASR-1006X. I have a mix of Juniper and Cisco routers all configured exclusively with IPv6. All of our routers are in the same ospfv3 area 0. We ...
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How does OSPF work on point-to-point Ethernet interface (i.e, 2 routers connected by a cable)

OSPF RFC describes two different modes of operation of OSPF for (1) point-to-point and (2) broadcast networks (and others). The operation on (2) involves selecting designated router and backup ...
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Why does OSPF use flooding despite using multicast?

We know that flooding is only possible in layer2 switch. But in OSPF router in layer3 uses flooding with multicasting. Suppose we have one router in OSPF uses multicast address 225.0.0.9. If router ...
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How in Distance vector routing one router communicates adjacent router through broadcast address and OSPF uses unicast with another?

In distance vector routing algorithm one router can communicates(shared the routing table) with adjacent router by broadcasting message which are in same subnet. OSPF uses flooding to unicast message ...
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osfp route filtering directly connected route

I am using Cisco 2960XR switch 192.168.1.0/24 is directly connected on gi1/0/1 192.168.97.0/24 is directly connected on gi1/0/7 router ospf 10 network 192.168.1.0 network 192.168.97.0 q1) how do i ...
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BGP <-> OSPF Route Redistribution Loops

In the following topology I have a multi-point redistribution from BGP <-> OSPF and I have recently encountered a routing loop. After further reading I have understood the problematic routers ...
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Traffic sent to GRE Tunnel fails, but GRE Tunnel is up and OSPF adjacencies are formed

NEW INFO_7-12-21 R1#sho ipv6 rout 2001:db8:B2:200::2:2 Routing entry for 2001:db8:B2:200::2:2/128 Known via "static", distance 1, metric 0 Route count is 1/1, share count 0 Routing ...
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I cant Ping from lan 192.168.44.0 and 192.168.45.0 , pc 3 pc 4

R0 and R1 are linked with ospf , and R1 with static route with MLSw. If i change R1 conn with MlSw to #ip route 0.0.0.0 0.0.0.0 g0/1 or g0/2 i can ping , but need help with static route conf ...
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PIM-SM over OSPF for mDNS traffic

I have connected 2 Routers via OSPF (using N links, N == 1 but it should be scalable to N > 2) and I am trying to have mDNS traffic go from LAN to LAN across the OSPF link, but I can't seem to make ...
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Huawei USG OSPF P2MP Network Limits

Good day! Configured an L2TP over IPSec tunnel on Huawei USG6500E. On the tunnel interface prescribed ospf type p2mp. I connect clients to this tunnel. When 32 clients are connected, the OSPF ...
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BGP-OSPF route injection doesn't work

Background: BGP is fully functional and works as expected so nothing need to worry about, the problem is the route injection between HK_Office <> HK2 and LON1 <> LON_Office, as you could ...
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OSPF with 2 Routers, N redundant links

I'm having a hard time trying to find a solution, and I can't seem to find anywhere on the web exactly what I need. We need to configure 2 Routers (MOXA EDR 810) to have N redundant links between one ...
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Can't ping neighboring router OSPF

I have set up an OSPF network and I cannot ping from the Edge router to Main Branch.
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Router on one side of a GRE tunnel not adding OSPF route through the tunnel whilst the router on the other side is

I have configured GRE tunnel between the Dublin and Carlow routers with the following commands: //Carlow int tunnel 0 ip address 172.16.12.1 255.255.255.252 tunnel source s0/0/0 tunnel destination 87....
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What are some real world applications of OSPF?

When I search for OSPF real world application or implementation, I always get the explanation of how OSPF works or how to calculate the cost. My question is, is there any real life scenarios of how ...
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Is it possible to have a second ASBR in my OSPF area 0?

I have three routers in area 0, two of which are connected to separate WAN circuits. I have one router that is sending the default route but when I try to add a second router with the configuration ...
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Why is OSPF more popular than IS-IS in enterprise networks? [closed]

I've read that IS-IS is more popular than OSPF in Internet Service Providers due to historical reasons (mainly that initially IS-IS had better hardware support and wasn't for IP only). But why did ...
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What is exact meaning of broadcast network in OSPF?

According to rfc2328(OSPFv2), broadcast network is "Networks supporting many (more than two) attached routers, together with the capability to address a single physical message to all of the ...
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Understanding the OSPFv2 MD5 authentication when packets contain LLS data block

When an OSPFv2 packet does not contain the LLS data block, then the calculated MD5 hash should be on the "Auth Crypt Data" field. For example, here is a LS Update message which does not ...
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Routing Protocols and sharing information

I am running multiple Protocols on different Routers as so: R1-RIPv2 EIGRP OSPF R2-OSPF and RIPv2 R3-RIPv2 and EIGRP R4-EIGRP and OSPF This is not a practical exercise, it is just to explore how ...
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3 votes
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Junos not automatically advertising an address configured on loopback interface to OSPF

According to JNCIP study guide(page 156) from 2003, the Junos should advertise a prefix on lo0.0 interface to OSPF if the RID is not manually configured: JUNOS software automatically advertises a ...
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OSPF Router ID election query [duplicate]

I have a query regarding ospf router id election. Suppose I have a router with 3 connected interfaces. 10.1.1.0/24 11.1.1.0/24 12.1.1.0/24 I have enabled ospf area 0 on network 10.1.1.0 and 11.1.1....
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Brocade OSPFv3 Routes are not installed

I am trying to deploy OSPFv3 across our network. However a few routers do not install the OSPFv3 route's to their routing tables. For example, this router is able to ping a certain host on the network....
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How an OSPF network react when an attacker deactivate one of the network interfaces on the router?

I am a bit stuck with OSPF. Want to know how an OSPF network react when an attacker deactivate one of the network interfaces on the router? What are possible impacts on the network if this ...
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OSPF route advertising same subnet in same area 0?

Now: SW02 currently running OSPF area 0 with redistribute connected subnets which includes VLAN10 with another router/switches which isn't in the picture and not in the scope of this question; VLAN10 ...
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How should OSPF work over WiFi? [closed]

I've had problems running OSPF over my WiFi network, and it seems to be related to multicast. The routers can't maintain a neighbor relationship, and when I watch the packet traffic I see one router ...
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Layer 2 redundant network and OSPF

What is a recommended way (in terms of maintenance, simplicity and failsafe-ness) to essentially run a "ring" of switches, but allowing OSPF to run properly (so equal-cost-path routing can work - in ...
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Are OSPF standard areas consisting of only one router any use?

I am currently reviewing the OSPF configuration of an existing network in an attempt to streamline it. From a Layer 3 standpoint, this network consists of two core routers in Area 0 (CORE1 and CORE2) ...
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Connecting layer 3 switches together without trunking

I currently have 2x Juniper EX4200 and I'm looking into changing it into Ubiquiti EdgeSwitchs. The diagram: SW01 and SW02 are connected to each other using OSPF P2P. Both of the switches have their ...
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why does the show ip protocols command at each router for ospf router output not showing any Routing Information Source for all loopback 0?

NarS-R1(config)#router ospf 1 NarS-R1(config-router)#network 192.168.12.0 0.0.0.255 area 0 NarS-R1(config-router)#network 192.168.17.0 0.0.0.255 area 0 NarS-R1(config-router)#network 1.1.1.1 0.0.0.0 ...
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"ospfNbrIpAddr" parameter in RFC 4750 page 53

in RFC 4750 page 53, there is a parameter called "ospfNbrIpAddr", I am not sure exactly what it means. Suppose I have two router, they are connected through physical ethernet port1, router A port1: ...
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Do DR-Other router forwards Type 2 LSA received by DR?

In the Diagram below when R1 is newly added to Network Topology R1 and R2 become neighbors and exchange Type 1 LSA from R2, R3, R4. But how R1 knows Network LSA created by the DR in LAN(subnet 1). ...
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OSPF neighbor not working

I'm currently designing a spine leaf network, 2 Spine switches and 4 leaf switches. btw this in packet tracer. So in order its Spine1# and Spine2#, then Leaf1#, Leaf2#, Leaf3#, Leaf4#, and addresses ...
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