Questions tagged [networking]
For questions about networking in general. Any question about all on topic network devices can use this tag.
308
questions
0
votes
1answer
12 views
Is an extra port opened when accessing localhost:port? [closed]
Imagine a program serves "Hello World" on localhost port 6000.
If I visit localhost:6000 in Chrome, is an intermediate port opened to send back the response? From the POV of the server, the ...
1
vote
0answers
10 views
What is the best way to match packets across pcap files from different capture points? [closed]
I have multiple pcap files which contain data from different capture points in the network.
Previously I thought that by using the IP-ID field I can match the packets across the capture files but I ...
1
vote
2answers
35 views
Using WAN IP for a host instead
I have a single static public IPv4 address from my ISP.
So I understand that i can just forward all traffic using port forwarding to one of my private IPs, but still I am wondering if this is the ...
0
votes
0answers
21 views
What would it require by a server and a connection to have 10000 TCP clients connected to a server pumping out 20k bytes per second? [closed]
Not sure if its the right place here but i am abit lost in trying to imagine what machinery is needed and network needed the following and dont really know what params to calculate upon :
A server ( ...
0
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0answers
16 views
How to connect internet just one site by using windows server? [closed]
I have 2 pcs with connected via Lan.
1st: windows server has 2 lan with internet access
2st: client pc (no internet access) but connected server with Lan.
I want to allow access one website on client ...
0
votes
0answers
14 views
How to Clear Cache? [closed]
We use a third party for website maintenance. When they make changes, we are able to see those changes on home computers, but the worksite machines still display the old site. I have tried "diag ...
0
votes
0answers
23 views
What is the data encoding and modulation technique for ADSL2+ and VDSL2? [closed]
A lot of journals mention that the modulation technique for both ADSL(2+) and VDSL(2) is the wired version of OFDM (DMT), but the Wikipedia page for OFDM states that OFDM in general is a method of ...
0
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0answers
18 views
What is the totaly delay? Question 5 options: 1000kb 2480ms 2280ms or 4285ms [closed]
Assume the following: (1) the propagation delay between browser and server is 100
ms, (2) the transmission rate of the link is 10 Mbps, (3) a web page, base HTML file
100 Kbytes in length, contains ...
0
votes
2answers
42 views
Congestion control in transport and network layers in TCP/IP
Why do we need congestion control in BOTH the transport layer and network layer in TCP/IP model. Cant we be good enough with control in just one of the layers only? And how do they differ?
0
votes
2answers
26 views
Ping responses to the Gateway
Last week, I have experienced a strange scenario with Adtran NV3448(a router) and an ISP circuit.
Adtran is a similar company like Cisco, also makes networking equipment such as Router, switches, etc.
...
0
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0answers
11 views
How does the IPv4 Total Header Length field & Fragmentation work together? [duplicate]
I recently learnt that the maximum value of the IPv4 Total Header Length field is 65,535 which equals approx. 65.5KB. To my understanding, it is different from the IHL field as it includes the ...
-1
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0answers
19 views
How can an 10.0.0.4 IPv4 Address be classified as Class A if it's surely a Class C address due to a subnet mask of 255.255.255 (/24)? [duplicate]
I've been studying for the CCNA using Jeremy's IT Lab's awesome course on YouTube. However, there is one seemingly contradictory detail in my mind regarding the IPv4 Address Class that was taught;
if ...
2
votes
2answers
93 views
What will happen if a server receives a duplicate SYN for an existing connection?
If a server receives a fresh SYN packet for a connection that is already established, what should it do?
I have already seen What will happen at server side if it received 2 SYN packet from the same ...
0
votes
1answer
34 views
Ethernet Frame visualization
One IP packet is fragmented in multiple ethernet frames at sender's side
And at receiver's end, all the frames are combined to get back the IP packet
So is there any way to see what payload each ...
0
votes
2answers
59 views
Why does IPv6 NS not use unicast address but multicast
This is a follow up of Why not put unicast address in IPv6 packet containing NDP neighbor solicitation instead of solicited-node multicast address?
The accepted answer makes no sense.
It states the ...
0
votes
2answers
27 views
What's the Destination unreachable ICMP packet(ICMP payload the UDP) usage? [closed]
In my Mac(192.168.2.228), it will send ICMP packet to my house's router (192.168.2.1).
with the info Destination unreachable (Port unreachable)
and in the Wireshark packet detail panel, there ...
1
vote
2answers
123 views
Is this UDP diagram wrong?
I was just wondering if anyone can tell me why all UDP diagrams I have seen list a request from the server to the client as the first point of communication? Take a look at the following diagram for ...
0
votes
1answer
24 views
How do I properly serialize a network packet [closed]
So I'm currently writing a program that is essentially just a server and a client. The idea is that I want them to be able to communicate with one and other by sending packets back and forth. And I'm ...
0
votes
1answer
18 views
Whether the Propagation delay contains the signal from chain into the cache queue?
From the wikipedia:
Propagation delay – time for a signal to reach its destination
and from the slideplayer.com I found the image:
there seems the Propagation delay represent the signal transport ...
0
votes
0answers
14 views
How to find which protocol is used by lower layers? [duplicate]
When we type https://stackoverflow.com/ all the data which is sent to this server would be using HTTPS protocol in transport level
So is it possible for me to know which error detection, flow control ...
0
votes
1answer
25 views
Why do baseband transmissions use TDM?
To the best of my knowledge, baseband transmissions use (only) time division multiplexing. Why is that so?
TDM isn't as efficient as statistical multiplexing. Why is TDM preferred for baseband ...
0
votes
1answer
34 views
How can i set up a Wireless LAN to serve 20,000 concurrent devices [closed]
How can i setup a wireless LAN that can serve up to 20,000 concurrent devices. I am having a problem in figuring out if i need one router or several routers. A topology diagram with explanation would ...
0
votes
2answers
39 views
List of frequencies that a device can connect to over 2.4 and 5 GHz channels
When connecting to a Wifi on 2.4GHz or 5GHz channel, a device connects on a certain frequency. Is there a somewhere list of all possible frequencies that a device can connect to on a 2.4GHz/5GHz ...
0
votes
1answer
35 views
Sequence numbers and wrap around concept
I was reading an article about the topic and I came across this :"During connection establishment each party uses a Random number generator to create initial sequence number (ISN), which is ...
2
votes
4answers
101 views
What exactly is “network automation”?
When we say network automation, what "automation" are we talking about? What is that being automated?
I've heard that in network automation we do not have to configure each individual ...
0
votes
1answer
26 views
What are the benefits and drawbacks of NSPOF networks over SPOF ones? [closed]
NSPOF has redundant links and redundant network components, so I think the biggest benefit it has over SPOF is high fault tolerance and the biggest drawback is the high cost of buying and maintaining ...
1
vote
1answer
17 views
Session layer role(with example) in OSI Model [duplicate]
Could someone provide some real world scenerios to understand the role played by session layer in OSI model.
Example:
Presentation Layer handles zip&unzip etc.
Similarly what does session layer ...
0
votes
1answer
42 views
Some mobile clients are unable to connect to UniFi AP mysteriously
We have two UniFi Controllers, one contains the main internet its directly connected to the fibre and then we give internet to the second controller using LAN connection, internet works fine in main ...
0
votes
1answer
25 views
confused with transmission delay
I was reading a textbook which says:
The transmission delay the amount of time required to push (that is, transmit) all of the packet’s bits into the link.
Does it mean that transmission delay is ...
0
votes
2answers
55 views
can't send packets if the link is currently busy?
I'm new to networking sorry if my question sounds dumb, I was reading a textbook which says:
the outbound link for the packet is the one that leads to router B. A packet can be transmitted on a link ...
0
votes
1answer
54 views
Network Protocol vs Framework?
I've been a network engineer for almost 4 years now. I thought I understand what a network protocol means. but now I'm having doubts.
For me,
Ethernet is a protocol used at layer 2. there would be ...
0
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2answers
44 views
Layer 2 managed switch and layer 3 switch
If you have layer 2 managed switches which have VLAN's on them, do you still need a layer 3 switch/router?
0
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2answers
23 views
why sometimes we need to use Broadband Transmission (Using Modulation)?
I was reading a textbook which says:
Baseband transmission requires that we have a low-pass channel, a channel with a bandwidth that starts from zero. This is the case if we have a dedicated medium(...
0
votes
1answer
26 views
How to identify Digi CM Console Server via command line/SSH?
Digi CM Console Server is a Secure Access and Management for Servers and Network Devices
https://www.digi.com/products/networking/infrastructure-management/console-servers/digicm#overview
How do we ...
0
votes
3answers
48 views
Can the network devices run out of ephemeral ports due to high use of websockets?
This might be a really stupid question, but something I really want to understand.
My understanding is a tcp connections staying open indicates that each of the network devices between the client and ...
0
votes
1answer
39 views
iperf3 UDP tuning
I am trying to test throughput in the network. But when i start iperf3 client for sending UDP packets it sends TCP SYN packets. Why does it behave like this? (it should not send udp tcp syn while ...
2
votes
6answers
2k views
Why can't we create a hierarchy of hubs?
I was reading the Comptia Network+ All in One book and I came to know that we cannot create a hierarchy of hubs. My question is why so? Are MDIX ports simplex? Why is it not possible for the hubs to ...
0
votes
1answer
34 views
Unicast and Multicast MAC address convention
I need help in understanding how Unicast and Multicast MAC address is differentiated as explained in wiki.
According to what I understood, when the least significant bit is set as 0 in the first octet ...
0
votes
1answer
20 views
Does Telnet need to be activated on both devices I am using or not? [closed]
I've searched everywhere for the answer to this question but can't find a simple yes or no.
Basically, I have a virtual server hosting some services and then a physical panel PC in another part of the ...
0
votes
2answers
103 views
Routers and layer 3 switches for connecting two buildings on site using fiber
I understand layer 3 switches are essentially routers, but often don't have the capabilities a router has, e.g. NAT. So I'm trying to work out where it would be necessary to have layer 3 switches vs ...
0
votes
1answer
71 views
Is it possible to setup IPsec behind NAT without port forwarding?
We want to setup a IPsec connection between customer sites and our office so we can manage the hardware we place at customer sites (e.g. barriers). Its important that the VPN connection stays up all ...
1
vote
3answers
67 views
Assigning IP addresses to multiple switches
Thank you in advance for taking the time to read my question, i appreciate it. I am in need of help on IP assigning to 4 brand NEW Araknis switches that I am replacing with the current netgear/tp-link ...
1
vote
1answer
93 views
Do mobile phones continuously broadcast their IMEI number so that cell towers can find them?
Edward Snowden said that in an interview. Is it exactly true? Does it have to do with SSN (sim serial number)?
Is the SSN broadcasted with encryption and modulation done to it or is the IMEI number?
1
vote
0answers
11 views
5g authentication method for IoT [closed]
While i was studying authentication methods in 5g i bumped into 3 authentication methods that seems to be the most important ones: 5G-AKA,EAP-AKA,EAP-TLS.
Which one of these three could be more ...
0
votes
1answer
63 views
TCP Handshaking Meaning of RST
I am trying to implement TCP handshaking but receive RST instead of ACK:
No. Time Source Destination Protocol Length Info
62 24.622012890 192.168.0.147 ...
0
votes
3answers
49 views
Why is the trace route to a particular IP not the same as trace route from that IP to mine?
So i am running a trace route from http://www.speedtest.com.sg/tr.php to my system. i get a route. And i run a trace route from my system to the website above i get a different route. Why is that? Why ...
0
votes
2answers
43 views
Reconciling multiple definitions of Bandwidth
I am confused about the meaning of the term 'Bandwidth' in a wireless transmission environment. The two most common definitions I could find are:
difference between the upper and lower frequencies in ...
0
votes
2answers
39 views
Modify the IP in TCP/IP packet
My ip address is specified in the ip packet sent to the next node. I wonder if a device that handles this packet can modify the ip address before forwarding it to the final destination?
In theory ...
0
votes
0answers
13 views
CCNA static IPv6 interface id understanding question [duplicate]
Hello,
Can anyone advise why I would add ::1 to a subnet in IPv6? In this case I am looking to use the global unicast address and not the link-local even though I would normally do this.I would add ...
1
vote
1answer
44 views
Can people with an ISP access your network if it is on the Default Free Zone?
Let's say you have a router on the DFZ (despite costing an absurd ammount of money). Would your network work the same as if you have an ISP in terms of web hosting, etc?
Can people still access your ...
