Questions tagged [networking]
For questions about networking in general. Any question about all on topic network devices can use this tag.
466
questions
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11
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best books to learn gns3 [closed]
I need books to improve my knowledge in networking, What are the best books to learn GNS3?
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7
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Appserver wont turn on after getting into different network [closed]
I have built a web app in virtual box, which runs on cent os. Which has a database, crm service etc. The ip assigned is static all the service run in a single server. The ip used is 192.168.1.74. All ...
-1
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0
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13
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Wireless network setup for a whole building [closed]
I want to locally host a node js backend website that is only going to be available on a lan connection. The location i want the network to be available is a 1300 m^2 area 15 story building. The whole ...
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24
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How to prevent MAC spoofing with a captive portal? [closed]
Wireless Setup
I have a WiFi network.
When someone connects their device to the network, they are taken to a captive portal.
When they provide a code, their device is granted access to the internet.
...
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0
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25
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Perform port forward on 169.254.0.1 device [closed]
I have teltonika router on a mobile connection
Lets say the ip is 10.132.141.25
On the lan of the router I have a device that is default setup to have the ip
IP = 169.254.0.1
Mask = 255.255.0.0
...
- 101
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15
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Routers randomly throttle/drop all connections [closed]
I have an incredibly weird and hard to diagnose problem.
The router of our network started dropping all packets at random for a couple of minutes at a time, it kept doing so despite numerous setting ...
0
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0
answers
24
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OSPF - How does slave know what to send LSR to when DBD is not shared by the master
Consider a topology where R1 and R2 are connected.
R1 has following networks. 192.168.1.0/24 192.168.2.0/24 192.168.100.1/32
R2 has following networks. 192.168.2.0/24 192.168.30.0/24
192.168.2.1 and ...
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1
answer
42
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Basic question on 'network history based routing tables'
I have encountered the following sequence of words: 'routing table formed on the basis of network history information'. I know that initially, routers discover neighbor nodes and therby the possible ...
0
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1
answer
23
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How router will send ARP resolve packet when it receive ARP request?
How router will send ARP resolve packet when it receive ARP request ??
Router by default enabled with proxy arp configuration?? If then proxy arp is not configured then what will happen if it receives ...
- 127
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1
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25
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Is it possible for mobile devices to connect to a far away ASN?
I am trying to understand how the internet connection of mobile devices is done. Knowing that BGP is used for the communication, I would like to know is it possible for the mobile device to connect to ...
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2
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64
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How to benchmark time a packet spend in each OSI layer?
I'm benchmarking latency of sending a TCP packet from a client to a server. The payload of the packet is the nanosecond timestamp (using clock_gettime() on Linux) right before the send() socket ...
- 103
1
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1
answer
22
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Configuring shared uplink on l3 dell s4128f-on
I have a Dell switch s4128f-on which I'm using as L3 core switch. What I want to achieve is creating multiple vlans and being able to reach other networks through an uplink.
What I've done so far is:
...
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1
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0
answers
12
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Port mirroring traffic on Hyper-V not showing Layer 3-7 traffic [closed]
We've been experiencing some issues with port mirroring that is used by a Network Intrusion detection system. Our company uses AlienVault as a SIEM and uses a Hyper-V sensor which is used to forward ...
- 11
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12
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What would be the correct way to go about subnetting an IP address for two networks? [duplicate]
I am struggling with how to proceed with this. I have started by converting the IP address into binary. If somebody could just give me a push in the right direction I would appreciate it!
There are ...
0
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1
answer
16
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Can refer a detailed low level explaination of the OSI model at operating system level? [duplicate]
I understand the function of each layer in OSI model but I can not comprehend the inner working at the operating system level. I can't mentally picture the life cycle of data from application layer to ...
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2
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42
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Simple IPv6 Global Unicast question
I was reading this article which states:
RFC 3587 states that out of the 128 bits in IPv6 addresses, left most
three bits are must be fixed as 001. Remaining 45 bits are reserved
for global routing ...
- 103
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3
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53
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How to use IP pool
I am just beginner, I just want to setup my mini data center and for testing i get a FTTH connection and /30 ip pool, ISP reply is something like that, "IP Pool 103.15.xx.xx/30 has been assigned ...
2
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2
answers
54
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Why is a PoE circuit limited to 328 feet?
I'm trying to learn about PoE and a friend told me the 100 meter limitation on a PoE circuit is because of the DC voltage drop on the power channel, not the data. I had understood the opposite, that ...
- 131
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2
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40
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Do PoE lighting systems require a separate network from other PoE systems?
I'm new to networking and PoE but am trying to understand it enough to explain myself. I recently spoke to a Genisys lighting rep who told me their systems couldn't be on the same network as an IP ...
- 131
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2
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37
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Extreme 210 fiber port not connecting
Let me preface my question by saying I'm not a network admin and don't know nearly enough about networking.
I have an Extreme 210-12p-GE2 switch.
My problem is that the fiber port that was working is ...
- 113
2
votes
2
answers
82
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Why iBGP speaker should not modify next hop address?
I understand the concept of "Split Horizon" that an iBGP router A learns an external route from an iBGP router B, thereafter, iBGP router B will not advertise the same route to other iBGP ...
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3
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5
answers
225
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Why should I use vlans instead of subnets?
I know that this might be a trivial question for the more experienced. However, I am a student who has just started designing networks.
Assuming you have to design a network of a school divided into ...
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36
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In an SDN (OpenFlow), are all switches directly connected to controller?
I found this question how openflow messages get routed from switch to controller? (SDN)
And in the answer it says:
In SDN networks all OpenFlow switches are directly connected to controllers.
But if ...
- 395
2
votes
4
answers
156
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How does ARP work, when the host with known MAC address is moved to another subnet
I've been trying to figure out this for some time, but I'm quite lost.
Assume you would have 3 networks -> A (PC0), B (PC1) and C
How would ARP behave, if it already knew all MAC addresses from ...
- 21
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3
answers
77
views
Are WAN and "backbone" same?
As a non-network engineer, I came across the term "backbone". The situation only requires a casual understanding of it, or even fine without it, but I was interested to do a light research.
...
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1
vote
2
answers
180
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EEM Script Using Variables
I'm wondering if it's possible to build an EEM script that will shutdown, wait, and then enable a router interface based on a syslog message. I know I can get this to work if I specify the interface ...
- 130
1
vote
1
answer
33
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What could be the bottleneck of my load-testing case?
I need to bring up a bunch of my devices in the network to hit some other service, for testing purposes. And I have used GNS3 to simulate that.
As you may find in my GNS3 project, I have such ...
- 111
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2
answers
53
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unable to ping loopback interface gns3
I have the following gns3 topology
I'm unable to ping R1 loopback interface (destination host unreachable)
I'm not sure what is wrong
R1 configuration are shown below
hostname R1
!
boot-start-marker
...
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2
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48
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how cisco switch handle the incoming frame
[
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4
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110
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ARP requests from a different subnet
Not sure if my question is on-topic here. I found the following question about ARP requests from a different subnet and I was wondering if and when this is an actual use case. The original question is ...
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20
votes
5
answers
4k
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Why is Packet Size Limited?
I was reading: this answer to "Maximum packet size for a TCP connection", where it says:
The absolute limitation on TCP packet size is 64K (65535 bytes), but
in practicality this is far ...
- 303
2
votes
2
answers
85
views
Can Loopback IP be Public
I have a Usecase where an Access Device need to reach a Core Device over the Internet. Access Device is configured with the Public IP of the Core device as of now so that it can reach the Core over ...
- 21
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1
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31
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Why need Ack flag if we already have ack number in TCP
If we have ack number so from there we can trace that how many bytes are received and which byte is need next so then what is the use of Ack flag there?
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1
answer
109
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How to reset a Default username and password of Allied Telesis AT9000/28 switch using CLI? [duplicate]
How to reset a Default username and password of Allied Telesis AT9000/28 switch using CLI?
1
vote
2
answers
61
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Can networks with different netmasks overlap?
Let it be this diagram:
Can I assign such networks at each segment without overlapping? In my understanding each network has a range of usable IPs and those ranges overlapps each other.
For instance, ...
user80646
4
votes
1
answer
312
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what are the difficulties of configuring switches through SNMP?
I have a cisco switch that supports CLI, SNMP, and NETCONF for management issues. I should develop an application for managing the switch which should include monitoring and also configuring ...
- 165
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1
answer
87
views
Is the "ping" command a broadcast message?
I am learning about how ARP works and I have some questions regarding the ping network utility.
ping is used to test connectivity and reachability between devices. PCs have their own ARP table where ...
- 195
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0
answers
11
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Why wifi channel 6 is supposed to be a good channel in generel? [duplicate]
lets say that we have 44 wifi 2.4GHZ 802.11b/g/n routers each can use any of 11 channels and each channel have exactly 4 routers. In this situation I can see that only channel 1, 11 are my best ...
- 101
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1
answer
51
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Tagged-only VLANs
I have an HP ProCurve swicth configured as follows (simplified, with U for Untagged and T for Tagged):
VLAN_1:
U 1,3,5,7-10,12-16
T 2,4,6
No U 11
VLAN_2:
T 1,3,5
VLAN_3:
T 1,3,5
What is the purpose ...
- 103
1
vote
3
answers
72
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Longest Prefix Matching
I just learnt about this concept and I have a query which was also asked by someone earlier but was grossly misinterpreted.
Suppose my Router has Routes for Networks: 192.168.22.0/23 and 192.168.22.0/...
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2
answers
76
views
Does window size in tcp header include tcp header size?
Let's say a TCP segments has in the field of "window size" = 1400 bytes.
Does that mean that
we can send 1400 bytes counted in tcp segments = TCP headers + data
or
it does specify only ...
- 103
1
vote
2
answers
50
views
Best way to configure layer 2 daisy chain with 2 layer 3 switches/gateways at either end?
I would like to implement a linear daisy chain for the purpose of transmitting internet over a considerable distance.
One motivation behind the use of a linear daisy chain for this problem is that ...
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1
answer
66
views
What will be the sequence number consumed by FIN flag? [duplicate]
In the connection termination phase, suppose the FIN segment from the client-side contains data ranging from sequence no 100 to 200,
So will the ACK no from the server start from 201 or 202? Will the ...
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1
answer
40
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Question about private ip address and public ip address
Let say a company bought a range of ip 172.16.1.0/24 , my question is this range of ip is public or private? and another question why the company not using private ip address to subnet and use NAT to ...
user81911
2
votes
1
answer
75
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What Exactly are Digital and Analog Signals?
While researching networking, i came across the term "Digital Signals" and "Analog Signals". According to the majority of sources ive viewed online, people are saying that an ...
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vote
1
answer
54
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How can I use two WiFi routers with one cable to the ISP router?
Let me explain...
There is the fiber optic ISP router on the first floor, connected to it via LAN cable is a switch, connected to the switch via LAN cable is a WiFi router on the 7th.
I want to add ...
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0
votes
1
answer
30
views
Are passive scanners subset of active scanners?
Assuming:
Passive scanners are those which do not actively send request packets, all they can do is monitor packets (which can be probe replies and beacon frames) which are passing through the ...
- 101
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2
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62
views
Does MAC replace CSMA/CD in Ethernet?
We now that in old days Ethernet use CSMA/CD for collision domain. However, with the advent of Switches now MAC addresses are used to identify the source and destination machine. But still when I read ...
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2
votes
1
answer
53
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How Ethernet protocol is related to Ethernet types such 10BASE5?
I know that Ethernet is a Data Link Layer protocol which specifies how the communication takes place b/w nodes in LAN defined by standard IEEE 802.3. I came across a book in which there were different ...
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5
votes
1
answer
1k
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Does an unmanaged switch deal with IP addresses at all
My belief is that an unmanaged plug-and-play layer 2 network switch only deals with MAC addresses.
When computer A on a local network wants to communicate with computer B for example through the ...
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