Questions tagged [networking]

For questions about networking in general. Any question about all on topic network devices can use this tag.

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Questions about logical-systems of juniper

In my Juniper MX480, the logic-systems config is below: [edit] logical-systems { r1 { interfaces { ge-0/0/0 { unit 0 { family inet { ...
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Is it possible to configure Cisco ASR901 as a layer 2 VLAN switch?

I have been fiddling with a Cisco ASR901 for a while now, but I can't wrap my head around configuring it as a layer 2 VLAN switch. Is it not possible to configure one of its Gigabit Ethernet ports as ...
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1 answer
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what are scenario where re-transmission packets can been seen in wireshark logs

While troubleshooting i came across this challenge ,able to see retransmission packets continuously in packet capture . please let me know in what scenarios this retransmission packets are seen.
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1 answer
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what is significance of proxy id while configuring site to site vpn tunnel . why we should use proxy id and in which scenarios

i came know about proxy id configuration for first time. when iam troubleshooting site to site vpn tunnel configuration along with vendor . post configuring proxy id issue got resolved . But iam still ...
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-1 votes
1 answer
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Why is Cisco router PPPoE client configuration so complicated? [closed]

In some routers like Ubiquiti's UniFi Security Gateway, when you want to connect to internet via PPPoE, all you have to do is go to the web GUI or controller, go to WAN settings, hit the dropdown ...
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3 answers
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Why does a queue of a network device like router starts to fill up if the arrival rate equals the transmission rate of the outbound link?

In the book "Computer Networks: A Top Down Approach by Kurose" it is written that when the traffic intensity approaches 1, the average queue length gets larger and larger. Traffic intensity ...
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1 answer
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Establish a network between two remote systems

Is it possible to create a network between remote systems without internet? if true; how?
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1 answer
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Why I am Getting %100+ Network Usage From SNMP? [closed]

I am using SNMP in Ubuntu 20.04 to get the network usage info and I am using this formula to calculate the network usage: InOctets : The difference between two poll cycles of collecting the snmp which ...
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1 answer
96 views

test etherchannel load-balance command doesn't work

I am trying to learn the etherchannel environment but when I enter this command it gives an error. Switch#test etherchannel load-balance interface po1 mac 00d0.ba86.1e19 00d0.ba86.1e1a ^ % ...
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1 answer
851 views

What are the differences between root primary and secondary?

Hello I am new at networking and studying for CCNA. There is a paragraph like this in the book and I am struggling about understanding well. Maybe it's because english is not my native language. ...
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2 answers
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Why the iBGP's loopback network is not valid in AS?

This is my test topology: this is my Routers' detail configuration: <R1>display current-configuration # sysname R1 # router id 1.1.1.1 # aaa authentication-scheme default authorization-...
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1 answer
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How does STP attack work?

I was reading how STP works and an idea came to my mind. I thought about an attacker can add a new switch (somehow, i don't know if it can be done remotely) or can manipulate the existing switch's ...
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1 answer
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Why the iBGP received network is not valid?

I test the BGP in my PC, this below is the topology: R1--(eBGP)--R2--(iBGP)--R3. and R2-R3-R4 are in OSPF(omit details). this is my detail configuration of BGP: [R1-bgp]dis this # bgp 100 peer 10.1....
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2 votes
2 answers
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How does the VTP Client update it's information if the revision number is equal?

I am new to networking and my questions may be a bit weird. Please correct me if I am wrong. According to what I understand, Client updates it's information with the Server's if the Server's revision ...
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1 answer
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Understanding the BGP Peer point, BGP Peer and BGP peering session

In my test case, there have 3 ASs. the connections is below: I want to use this case to understand the BGP peer , BGP peering point and BGP peering session. in my understanding: BGP peer means the ...
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1 vote
1 answer
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Why the route comes from different AS?

Before, I know the AS path of BGP properties, such as the 200 100i means the route originate from AS100, use network import the route and through AS200, however in my case: admin@MX480> show route ...
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1 answer
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Enabling interface TenGigE0/0/2/0 pls help

I'm trying to enable just one SFP+ port for testing a 10gbit NIC. I cannot, however, for the life of me find how to enable a port. To me, it would make sense to conf t interfaces TenGigE0/0/2/0 admin ...
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1 answer
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How routers route packets to a specific network

As I understand it, routers route packets to a specific network based on network id and of course the network id must be unique on the Internet, now the question is: maybe there are billions of ...
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-1 votes
1 answer
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What is the maximum number of networks in IPv4?

From my understanding, in IPv4 addressing, the first 2 octets identify the network, meaning 2^16 networks can exist. But that doesn't seem even closly enough as the population in even USA is above 300 ...
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1 answer
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Why CSMA/CD and CSMA/CA are classified as broadcast based?

In CSMA/CD and CSMA/CA , why the Communication mode for these two access methods are classified as Broadcast based ? For CSMA/CA a Node sends a broadcast message to notify the other nodes on the ...
-1 votes
1 answer
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IS Network automation kills carries of network Engineers? [closed]

Iam working as network engineer since long time and i enjoying working same . But now i am afraid after listening of network automation .Is network automation kills jobs of network engineer across ...
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0 votes
1 answer
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Unable to Communicate from server to other servers after migrating from existing firewall to new firewall

In our existing environment we had migrated old firewall with new firewall after this activity . we had faced connectivity issue . From servers unable to reach other servers . Post clearing ARP table ...
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0 votes
1 answer
92 views

For UDP traffic reverse route is required or not

when compared to TCP protocol, UDP is non reliable protocol no knowledgement packet is required for previous packet before sending new packet . so in this case reverse route configuration is required ...
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0 votes
1 answer
50 views

Very confused on this part , two network interface Card(NIC) are configured on server [closed]

i am very much confused on this scenario . This is first time i am seeing two NIC cards are configured for server ,now my query is how to route traffic initiated at server end for NIC interfaces
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2 votes
1 answer
398 views

What might be the potential impact on increasing or decreasing MTU size of packet in network

i am looking eagerly to know the potential impact on network while and after changing maximum transmissions (MTU ) from 1500 default value to any other value .
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0 votes
2 answers
35 views

Why Ping Reply Succcess from different subnet IPs

In the university lab, i manually added IP in two ubuntu machines. PC1 IP 10.129.2.33 255.255.0.0 and PC2 IP 10.129.2.165 255.255.255.0. I connected first both computers with direct ethernet cable ...
2 votes
0 answers
108 views

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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1 answer
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What is the difference between these two different network security devices?

I have a choice between these two network security appliances, however the only difference I can see is the year and I don't know what that year means. SONICWALL TZ300 WIRELESS-AC SECURE UPGRADE PLUS ...
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1 answer
1k views

iperf between two computers on different networks [closed]

Is it possible to check bandwidth using iperf between two computers on different networks(i.e geographically apart)?. I researched a lot and every answer on stack exchanges or any other website ...
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0 votes
0 answers
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Is there any way to send different data packets together over wireline/wireless link? [duplicate]

I would like to know if there is a technology that allow to send many packets (of different data) together and at the same time over communication link (whether in wireline or wireless networks) of ...
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2 votes
2 answers
163 views

How does Network Layer behave when client received a unicast DHCP offer?

I went through various stack exchange post to understand the concept of DHCP offer when it comes as a unicast to client from the DHCP server. A server can send a unicast DHCP offer since it knows the ...
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WAN Frames vs. STS-1 and T1 Frames

I am having trouble understanding the need for WAN frames, such as PPP when using the SONET Protocol or T-Carrier System. Since SONET uses STS-1 frames and T-Carrier uses T1 frames, why is there a ...
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1 vote
1 answer
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I have issue with MSS and window size [duplicate]

I made a short example because I have tried understanding the difference between MSS and window size in tcp header when we consider a sender and a receiver. So let's say sender and receiver use the ...
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1 answer
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In gnss3, why can't I ping my cisco router from my VM?

I have the following network, I have never configured a Cisco router before so I'm having a little trouble. In router R1 I used the following commands to assign an ip to the router: configure terminal ...
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0 answers
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Why do we need IP and MAC addresses? [duplicate]

so I have just stared to learn OSI model and I can't understand why do we need IP on the third layer AND MAC addresses on the second layer. From what I understand MAC addresses are used to move frames ...
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0 answers
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What is the use of a host mask/ wildcard with respect to subnetting and ranges? [duplicate]

Taking the example of 10.0.0.0/20, that means my range is 10.0.0.0 to 10.0.15.255 I got that range because I know that the wild card is 0.0.15.255 and I just add it with the beginning address 10.0.0....
1 vote
1 answer
381 views

Why does this ip address give me an error "must be valid ipv4 cidr"?

If I set up an AWS VPC with CIDR of 10.0.0.0/20 then the range is 10.0.0.0 to 10.0.15.255 I make a subnet now. Why does 10.0.15.15/28 give an error. Isn't it's range 10.0.15.15 to 10.0.15.30 which is ...
1 vote
0 answers
53 views

Why did the IANA specifically choose these ranges for the the private IP address space? [closed]

10.0.0.0/8 IP addresses: 10.0.0.0 – 10.255.255.255 172.16.0.0/12 IP addresses: 172.16.0.0 – 172.31.255.255 192.168.0.0/16 IP addresses: 192.168.0.0 – 192.168.255.255 Is there any reason behind ...
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2 answers
31 views

Network Cable Flow Rate vs Propagation Speed

I was reading about network Cables then I saw some information that made me feel confused for example : if we say have a we have copper wire (e.g. Twisted pair) that can achieve a flow rate of 10 Mbps ...
2 votes
2 answers
56 views

How Access points differentiate stations?

I'm doing a ping from a station to another connected on the same access point. Given the fact that they are both on Wi-fi interface, how can access point know where to forward a packet?
1 vote
4 answers
992 views

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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1 vote
1 answer
267 views

How to block telnet access for one particular network from all networks except one using Extended ACL

Scenerio is given in the picture. I want to block all the networks except 192.168.5.128/25 from doing telnet of 192.168.5.0/25.
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1 vote
2 answers
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Do DSLAM and OLT function like a switch?

Let's say for example we have the following hypothetical topology: In each network, can each user communicate with each other? For example, can User 1 ping User 2?
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1 vote
2 answers
1k views

How to Change the Date on Cisco Catalyst 3750x Switch

We are using cisco catalyst 3750x 24 port switch series How to Change the Exact Date(Singapore) on a Switch ASW-G-L09-001#show running-config Building configuration... Current configuration : 11883 ...
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1 vote
1 answer
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Cisco networking (difference between serial connection an copper straight through)

What is the difference between using serial connections (ex: serial DTE, DCE) as compared to using copper straight through in a connection between routers? Is there any situations where serial ...
0 votes
1 answer
101 views

Linux networking + mix of auto-negotiation of yes/no [closed]

we have 10 servers with Advertised auto-negotiation: yes as the machines with driver driver: i40e driver: i40e version: 2.3.2-k firmware-version: 10.51.5 expansion-rom-version: bus-info: 0000:12:00.0 ...
2 votes
2 answers
488 views

Fiber link loss on Cisco Catalyst 3750x series switch

I have cisco catalyst 3750x 24 port switch series switch, and the switch has C3KX-NM-10G module. Problem : I have connected fibre optic in SFP+ transceiver on G2/TE1 (Uplink).  After 7 to 8 hours, the ...
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2 answers
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How to find specific device in a network without brute force?

I have an Internet of things (IoT) device with known MAC address, which is connected to a network. First, lets assume that this network is large (subnet 255.255.0.0). Is there any "smart" ...
1 vote
1 answer
686 views

BGP Best Path Selection Algorithm

According to this cisco document (https://www.cisco.com/c/en/us/support/docs/ip/border-gateway-protocol-bgp/13753-25.html), shortest AS_PATH is the #4 algorithm in the sequence to evaluate, out of 13 ...
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1 answer
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Connect two places 400 meters away at 10 Gigabit

we are a small media company with 10 gigabit networking using a couple Netgear Switches and CAT6 Ethernet to all the computers in our office. We expanded to a new location recently which is around 400 ...
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