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For questions about routing, the process of selecting to which network path traffic is sent. Consider using a more specific tag if your question is about a routing protocol like BGP or OSPF.

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design - Cisco ACI and Nexus 7ks - best choice OSPF or EBGP

We have two data centers as shown in the picture. Data center 1 and data center 2. At each data center 1) Nexus 7ks have 3 VDC's configured . WAN_VDC is connected to Cisco ACI using L3 Port ...
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2answers
68 views

How a packet gets from source to destination or from client to server

I'm trying to understand how a packet gets from client to server. I understand that it leaves the local switch and heads to the internet to get routed to its destination but what happens inbetween? 1 ...
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1answer
30 views

Reach IP in Parent Network

We have a router (Router 2) inside a network (Router 1) with a client (Client in Router 2) that needs to make a TCP connection to a client in router 1. We only have access to configure Router 2 and ...
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Linux Routing Problem on redhat like distro (clearos 7) [closed]

I have what I assume to be a routing problem on a redhat like box that I can't sort out. The machine has 5 interfaces. For simplicity lets call them eth0 thru eth4. Things are setup in "gateway" mode ...
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Server with two NICs behind Ubiquiti ERX, connected to two separate private company networks with possible similar address spaces [closed]

We have a Ubuntu 18.04 Server running a web application that needs to be accessed by two companies. We have two NICs on the server, one goes to our local "shop floor" network (10.200.145.0/24) which ...
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4answers
138 views

Does a router always have two IP addresses?

So I got pretty confused with this question, and while looking online I've found several answers saying that a router does need 2 IP addresses at a minimum, but it isn't clear to me why. Lets say ...
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1answer
31 views

How to differentiate between classful network and subnet (beginner)? [duplicate]

I have just started learning from the ICDN1 official Cert book. I've just covered the concept of Classful Networks. However when introducing Subnetting, the example has me confused. It examples an ...
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1answer
39 views

Static Routes and selection

For what I know, Static Routes don't have a Metric. So, what if a Router has more than one Static Route to a Network? Let's say that on the topology below we have Static Routes configured, and R1 ...
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26 views

Odd Connection State Firewall (?) Blocking Behavior

I am observing the following: jchan-mbp15:~ jonathan$ sudo nmap -oG - 192.168.55.0/24 -T5 -sn -n --max-parallelism 256 --min-parallelism 100 # Nmap 7.70 scan initiated Wed Oct 3 22:53:35 2018 as: ...
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0answers
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How can we calculate the subnet mask for a given IP? [duplicate]

I have no idea how is the subnet written. Some says its not possible but then how some find the answer. when looking the IP address 12.23.34.22, first octet is in class A having the classful mask 255....
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1answer
35 views

Replacing IP address of connections from AWS towards SIP

We have installed a PBX on AWS and connected it to our on-prem Router via VPN. My on-prem router is connected to the SIP provider via a physical connection with another on-prem MUX device (device ...
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37 views

Track crypto map state when using Policy Based Routing on Cisco Router

I have kind of a challenge and need some advice if the configuration I want to do is actually possible. Please don't kill me, I know that the configuration is not very "nice"... We are using DMVPN ...
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1answer
62 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
45 views

Why are the routes taken by packets random using LPM?

Consider the Longest Prefix Matching (LPM) mechanism that routers use to decide which data link the packet should be sent next. Assuming that the router tables don't change, shouldn't the path the ...
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1answer
36 views

Network routing/WAN failover

Hi any one recommend me WAN Fail-over in Cisco 2811 router in virtual interfaces I already try this configuration. but its not working ip route 0.0.0.0 0.0.0.0 192.168.86.1 ip route 0.0.0.0 0.0.0....
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1answer
44 views

Network ( routing and switching) , security

In my company network i am installing new cisco2811 router but i have problem, my LAN network can not ping and access network. i get point to point internet from ISP. PTP IP is 192.186.86.200/24 and ...
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1answer
35 views

Does segment routing protocol steer packets based on best (longest) prefix matching?

In segment routing protocol, we know that the routing process is source steered. I'm struck to know if any best (longest) prefix matching happens to route the data packets? If so any clue about the ...
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1answer
30 views

How can I create a static route between subnets on sonicwall

I have a SonicWall and two Wifi Access Points (APs) connected to it. The secured WLAN AP is connected to port X0 with subnet 192.168.22.x and has our "Secure" clients, as well as a printer. The guest ...
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1answer
45 views

Routing Table Eligibility

I have an architecture which is that each remote site has 2 Dialer interfaces dialling into a virtual-template core which authenticates the sessions and applies attributes from a RADIUS server. OSPF ...
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1answer
33 views

MultiLayer Switch to Ping different Switches and routers under different VLANs [closed]

Hey Guys, So this is basically a small design of a made up university which has 3 campuses( the 3 routers).Each connected to 1 College(Switch) and each college connected to 3 other Schools(switches) ...
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2answers
467 views

When doing 802.1X port authentication, how does the switch know how reach the authentication server?

So, while I get the supplicant-authenticator-authentication server structure (for the most part), the part that bugs me is the step when the switch starts communicating with the authentication server; ...
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1answer
67 views

Cisco 2960 not receiving dhcp from the router

I have a problem with Dhcp of some the Vlans. here is how my network is : I have a router ASR1001, which connects 15 switches(2960) as a ring topology. each switch has a subinterface of the router ...
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3answers
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How not to route on a Cisco router

So we have a router, with a switch card interface, 8 ports Say I have 4 VLANs (A,B,C,D) on it, with 2 switch ports in each. Each VLAN (i.e. all ports) can communicate with each other, because ...
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1answer
35 views

Connecting Layer 2 switchport to layer 3 port

I have a config that I am trying to bring up, and in my mind it should work, but perhaps I am missing something. The idea is that one end of the link is a layer 3 interface on a router. The other end ...
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2answers
51 views

How to understand the default gateway generally refers to the 0.0.0.0/0 route?

I am reading a document: The default gateway generally refers to the 0.0.0.0/0 route, which is used when there is no clear routing entry to a destination address. How to understand this sentence?
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1answer
60 views

Unable to route Public IPs over private network

I have the following setup; Router A Interface 1: 23.128.1.1/24 Route added on Router A to access 10.10.0.1/24 via 23.128.1.2 Router B Interface 1: 23.128.1.2/24 VPN Interface: 10.10.0.1/24 VPN ...
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1answer
22 views

How to use a remote shell on a machine outside of network

I understand the differences between LAN and WAN addresses. My question is: while outside a network, how do you target a specific machine's address beneath a public IP? Since a public IP for each ...
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2answers
67 views

To what extent can ISPs control routing in a packet-switched network?

As an application developer my entire understanding of networks was a high level 'acceptance' of http request/response pairs along with some DNS addressing. Somewhere in the back of my mind I ...
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1answer
52 views

R2 and R3 cannot ping each other

below is a capture of the configuration. R1 can ping the other two routers but R2 and R3 can't ping each other. Any idea what my issue could be? Screen Shot 2018-09-03 at 2.57.00 PM.png Router2#sh ...
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1answer
30 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 ...
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what is a reverse nat and why would i need it? [duplicate]

Though I could find some definitions of reverse NAT (like from here), I couldn't really understand why it is needed. I'd really appreciate some examples. And please don't get confused with the "...
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2answers
55 views

Why does ip routing not take an even remotely direct route?

I ran a traceroute on a url to a server we own in New York. I'm in central Florida. Traceroute showed the request being directed to west Florida and then far south Florida before finally being ...
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How many IP addresses needed for a single wan link? [duplicate]

02.192.168.20.0/24 main network need to be separated into subnetworks based on the following requirements.(VLMS concept) a. 4 subnets with 25 devices each. b. 4 WAN links to inter-connect the sub ...
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2answers
85 views

Prevent OSPF routes advertised by other routers from entering the routing table?

I have a fairly complicated scenario that I've managed to duplicate with GNS3. Please see the attached image. In this scenario I have four "Branch Offices" each with their own router connected to ...
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1answer
30 views

Create Accounting for Internet and merge ADSL, is there any way? [closed]

I have 4 Simple Wireless ADSL Modem that 4MB, 8MB, 16MB, 40MB Internet BW. I have one HP Server with 4 Network Ethernet Ports. I have 7 LAN based PC's, 2 Network Printer and some wireless station ...
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81 views

Sophos UTM WAN interface doesn't respond to ARP requests

I've sent this very question to Sophos Support but I feel that asking here might increase my chances to get an answer. The short question is: what could be the reason for my Sophos UTM VM WAN ...
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2answers
75 views

EIGRP Routing Issues

I had an issues about EIGRP. But first, here's the topology : I've done EIGRP Routing, but it's kinda strange. PC0 -> PC1 is able to ping, PC3 -> PC2 is able to ping. But, I can't ping PC0 -> PC2, ...
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1answer
22 views

Connect office to multiple customer VPNs

First time post here so if this is off topic please let me know where to ask this question. A company that provides outsource billing services to multiple client companies using VPNs to each remote ...
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32 views

Juniper Filter-Based Forwarding

We have the following Juniper MX80 setup: set interfaces ae2 unit 200 description ISP1 set interfaces ae2 unit 200 vlan-id 200 set interfaces ae2 unit 200 family inet address 200.200.200.2/30 set ...
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2answers
37 views

Cannot reach 4th hop, pc as router, static routing

I'm trying to set a PC as a Router and somehow it's not working correctly. I have following setting: CLIENT A 192.168.21.1/28 l l 192.168.21.5/28 ROUTER X 192.168.21.25/28 l l 192.168.21.17/28 CLIENT ...
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2answers
70 views

Network Ten LTE Hubs Into One Network

I'm working through a tricky situation getting a field office set up out in a very rural area. There are ten 12' x 60' trailers being set up (2-3 metres apart from one another), each with varying ...
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2answers
41 views

Cisco Router 1800 series doesn't route internet

Working on an issue with a 1800 series Cisco Router. Router get's Internet just fine, can ping Google, Microsoft, etc.. Router is connected to a switch, switch connects 2 workstations running Windows ...
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1answer
26 views

Add a flow to OVSK for communication

I have created a torus topology in mininet by enabling sflow and connecting to POX controller for topology discovery. Below is the command. sudo mn --custom=sflow-rt/extras/sflow.py --link tc,bw=10 --...
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1answer
25 views

ASA static routes

I have an Interface (IF1) with 172.16.18.254 255.255.255.0 security Level 0. This one connects to a Firwall where the network 172.16.18.0 255.255.255.0 is located and the gateway to this is 172.16....
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57 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. ...
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3answers
343 views

What is the different between routing table and forwarding table?

What is the different between a routing table and a forwarding table?
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1answer
65 views

Routing and Bridging on a Layer 2 or Layer 3 device

The thing that intrigues me is, say I have a router and I configure it’s interface as a Layer 2 and have 2 Vlans on the same router. So if I want to transfer the data from one Vlan(say VLAN-10) to ...
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3answers
104 views

how to do inter vlan for same subnet

I configure two same subnet network(ip:192.168.0.2 & ip:192.168.0.3) into VLAN...so they wont communicating with each other...but now i want them to communicate with each other... For that i ...
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1answer
34 views

Help with this acl

This is what i am trying to do Deny the network that host 200.200.200.10 is on, telnet access to R3 Permit host 200.200.200.10 to telnet to R3 Deny host 200.200.200.10 all access to host 204.10 on ...
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3answers
96 views

How do routers intercept packets?

I'm trying to learn about iptables and port forwarding and I'm running into a very simple hurdle. If my understanding is correct, this concept applies when there is a local area network, a router, and ...