Skip to main content
Share Your Experience: Take the 2024 Developer Survey

Questions tagged [network]

For questions about Networking that includes design, and use of a network, the physical cabling, hub, bridge, switch, router, and so forth. Anything in relation to networking and its technologies.

Filter by
Sorted by
Tagged with
38 votes
3 answers
20k views

Why does the IPv6 header not include a checksum?

It is stated in Wikipedia that an IPv6 header does not include a checksum. What are the reasons that were behind this decision?
Paulo Tomé's user avatar
33 votes
2 answers
22k views

Is multicast on the public internet possible? And if yes: How?

Is it possible to use multicast on the public internet? If yes: How? Are special IP addresses required and where do you get them from?
Matthias Merkel's user avatar
23 votes
6 answers
6k views

What stops someone from configuring their network with IP addresses they do not own?

Here's the scenario. I was picturing a university that bought a range of IP addresses. I think their network would still be connected to an ISP (right?), but they'd have freedom to configure stuff the ...
Tiago Oliveira's user avatar
22 votes
3 answers
30k views

Difference between router and gateway

What is the exact difference between router and gateway? In Network configuration we set the default gateway IP address, but in reality we call the device configured with that IP address as router?
Raja's user avatar
  • 355
22 votes
1 answer
23k views

How multiple client connections are made to single web server?

Actually I am learning Computer Networks and while at it, I am confused in how a web server maintains multiple connections? Simply to state, I learned trough some googling is that sockets handles a ...
Sagaryal's user avatar
  • 361
21 votes
5 answers
6k views

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 ...
Algo's user avatar
  • 313
20 votes
9 answers
15k views

Why are IP addresses given to each interface and not device? What would the implications of that be?

Why do we need to give IP addresses to each interface? Wouldn't giving one to each device be enough?
Tiago Oliveira's user avatar
19 votes
5 answers
4k views

How is 8 bits sufficient for the TTL in an IP header?

The TTL (Time to Live) is an 8-bit field in the IPv4 header. It can take any value from 0 to 255. If this means that the packet can take a maximum of 255 hops (routers) on its way to its destination, ...
reddi hari's user avatar
19 votes
6 answers
9k views

Network latencies between opposite ends of the Earth

This is just out of curiosity. when I pinged domains such as bbc.co.uk and google.com (in California), I get latencies of around 5ms as below: 64 bytes from xx: icmp_seq=0 ttl=55 time=2.940 ms 64 ...
user avatar
16 votes
8 answers
29k views

Does TCP open a new connection for every packet that is sent?

This might be a silly question but a me and few buddies have been discussing the potential limitations of TCP. We have an application that is going to listen for clients (think of a gateway) and route ...
user0000001's user avatar
16 votes
2 answers
10k views

Network Gateways vs Interfaces

When looking at the contents of a routing table section on the Wikipedia article on Routing Tables, it contains a table as an example of a routing table with two headings which have an unclear ...
Alex W's user avatar
  • 273
14 votes
3 answers
2k views

Where can I use the IPv6 documentation prefix

We are currently building a networking course with a practical part where students have to configure a small network in a virtual environment. However, we are not sure what ipv6 prefixes we can use ...
sliebald's user avatar
  • 143
14 votes
3 answers
22k views

Why is symmetric NAT called "symmetric"?

After searching a while, I'm still not able to find a logical explanation on why is it called symmetric NAT. Where lies the link between symmetric NAT and that each request is mapped to a unique ...
marc's user avatar
  • 243
13 votes
2 answers
7k views

Who has control over allocating MAC address to device manufacturers?

As of my knowledge each MAC address is unique for each device like servers, computers, firewalls, switches and routers, proxies, etc. So my question is: who is responsible for allocating these MAC ...
user avatar
13 votes
3 answers
2k views

What is the least possible separation of two NICs with the same MAC address?

Suppose you have two NICs with the same MAC address, but not necessarily the same IP address. What is the least possible separation (in terms of number of switches, routers, different IP subnets etc.) ...
LapplandsCohan's user avatar
10 votes
2 answers
5k views

What is IP squat space

I came across this article and I'm trying to understand what is going on here, I found some packets on my network containing 22.0.0.0/8 and 29.0.0.0/8 IP range and It's based on: https://en.wikipedia....
Satish's user avatar
  • 4,379
10 votes
1 answer
19k views

What is the use of the IPv6 scope ID?

In the structure struct sockaddr_in6, the field sin6_scope_id is declared. What is the use of this member? How can we know from the IPv6 address and the prefix length the scope that it should use?
Bionix1441's user avatar
9 votes
5 answers
15k views

Cascading Switches. Will it affect performance?

I am really new to large scale networking and all I know is the basics. I will be doing a network for a huge workspace consisting of multiple offices. There will be a total of 308 Clients, with at ...
Aaron Alfonso's user avatar
9 votes
5 answers
943 views

Different Behaviour of a Router

There are 2 cases that I would like to point out: When the router is directly connected with 2 PCs like this, In this case, PC2 is able to ping PC3. I just configured the IP address of PC2 and PC3 ...
anonymous's user avatar
9 votes
2 answers
2k views

Why do IPv6 unique local addresses have to have a /48 prefix?

According to RFC 4193, unique local addresses will always have a prefix of FD00::/8.. but according to Wikipedia: The block fd00::/8 is defined for /48 prefixes, formed by setting the forty least-...
Isaac's user avatar
  • 276
9 votes
8 answers
5k views

Can Ethernet frames only be transmitted in a LAN?

In the LAN depicted in the picture below, am I correct in saying that devices do not have IP addresses? There is no router and also only Ethernet frames (with source and destination mac address would ...
TomTech's user avatar
  • 91
9 votes
4 answers
675 views

Abstract language to describe network deployments?

Is there any more or less standard/spec that is, vendor neutral, for network configuration language? Say, a VPC with networks and virtual machines would become an XML or JSON file. Something like, &...
J. Doe's user avatar
  • 217
8 votes
7 answers
4k views

How LAN works in video games if only one station is permitted to transmit?

I've read the in a LAN the data is transmitted in packets so as to allow only one station to transmit at a given time, so how could this be applied in video games LAN parties if only one device is ...
eis3nheim's user avatar
8 votes
3 answers
7k views

Need help understanding how packets travel across the internet

I've been learning about networks recently at a new job, and I did a presentation on what I've learnt so far. When I was describing the relationship between the datalink and network layer, I mentioned ...
jwoff's user avatar
  • 83
8 votes
2 answers
37k views

What is the voltage used in ethernet lines (UTP Cables)?

I am asking this because after doing some research I found some conflicting information. First, on Wikipedia page on Ethernet physical layer I found that the voltage on the lines is 2.5V. https://en....
yoyo_fun's user avatar
  • 1,541
7 votes
3 answers
1k views

Fiber between two sites - no signal lights

We need to have fiber connection between two sites (distance less than 300 meters from each other). Currently there is multi-mode fiber connected to old switches working nicely. Now we are updating ...
lingo's user avatar
  • 71
7 votes
3 answers
6k views

Is there any reason to use a hub over a switch?

Given that hubs are essentially the same as switches, as far as I know, except they share bandwidth between all connected devices, while switches do not, resulting in faster connections. I am simply ...
Ashtin Blanchard's user avatar
7 votes
2 answers
4k views

The best way to understand Vlans?

Every time i try reading about the configuration of a device and adding it to the network, i always face a problem. The problem is basically am not able to understand Vlan's, and how for example some ...
Saif Ahmed Yassen's user avatar
7 votes
1 answer
735 views

Router benefits in 2018 compared to a L3 Switch

What are the benefits nowadays to use a Router instead of a L3 Switch ?
bdes31's user avatar
  • 1,085
7 votes
1 answer
763 views

Cisco IOS Tcl - Overhead

I've not been able to find much in regards to TCL other than the Cisco PDF "Cisco IOS Scripting with TCL Configuration Guide" and I just have a few queries. I'm looking into potentially utilising ...
matthew walker's user avatar
7 votes
1 answer
1k views

Raw API data for Cisco Meraki CMX Dashboard

Has anyone worked with Meraki's CMX raw data feed and can help answer some questions? I came here to ask because I have found no conversations about Meraki's CMX API elsewhere and I imagined that ...
Dengar's user avatar
  • 171
6 votes
3 answers
4k views

Why can PPPoE connect to a gateway which is not in the same subnet

We know the host needs to be within the same subnet as its gateway for the routing. However in PPPoE, the public IP has a 255.255.255.255 subnet mask, it means that the IP is not in the same subnet as ...
Anning Wuwang's user avatar
6 votes
4 answers
249 views

Packet Collison Avoidance

If a wireless network has collision avoidance, how comes the network slows down if more clients connect to it?
LtMuffin's user avatar
  • 163
6 votes
2 answers
2k views

Is a point-to-point T1 line literally a line in real life?

In Packet Tracer this is how we draw a WAN link, or a T1 link: Does the "red line" here literally means there is a single cable connecting the two routers in real life? If no, then what are ...
Noob_Guy's user avatar
  • 491
6 votes
3 answers
1k views

What is the characteristic of spoofed ARP packets?

Hi what is the characteristic of spoofed ARP packets? I want to know how to detect it but before that I have to know how can I call a packet a spoofed packet. I hope you can help me thank you.
Tiffany's user avatar
  • 85
6 votes
2 answers
3k views

How does a TCP segment fit into a smaller IP packet?

The IP protocol can handle fragmentation and it includes the fragmentation offset and identifier. I know this comes into play when your IP packet is too big for some specific network or link where the ...
Lucas's user avatar
  • 235
6 votes
2 answers
587 views

how to find the right value of MTU Jumbo frame

we take the decision to set jumbo frame on all our linux machines we have hadoop cluster with master machines , workers machines and kafka machines our switches ( Cisco ) are suitable to Jumbo frame ...
yael's user avatar
  • 61
6 votes
1 answer
2k views

Cisco HSRP CAM vs ARP timeout

Today we received email from our ISP saying they are performing maintenance on their network so if you have HSRP connectivity with them in that case you need to clear ARP table or reduce ARP timeout ...
Satish's user avatar
  • 4,379
6 votes
2 answers
7k views

What do exclamation '!' and period '.' mean in a switch config file

what do the ! and . mean in switch config files? Current configuration: 1363 bytes ! version 12.1 no service pad service timestamps debug uptime service timestamps log uptime no service password-...
robinhoodjr's user avatar
6 votes
2 answers
668 views

Can you become your own ISP?

How exactly does an ISP connect you to the vast network of computers which is the internet? In my area there are several ISP's. For example. Bell, Rogers, and Cogeco all connect you to the "same ...
Dougie Fuoco's user avatar
6 votes
2 answers
12k views

Do i need to configure VLANS on my router/firewall or just the switch?

I finally took time to map my entire shitty network to understand exactly what the guy before me did, and i must admit i'm a little bit surprised even if i'm not a network expert... Just take a look ...
Thierry Dalleau's user avatar
6 votes
0 answers
738 views

Cisco nexus 9396 rebooted with reason xbar_client

Today my one of cisco nexus 9396PX switch got rebooted and this is what i found, based on following logs what could be wrong? We don't have Cisco support for this switch, trying to see if i can get ...
Satish's user avatar
  • 4,379
5 votes
5 answers
2k views

How does the shortage of IPv4 public IPs influence existing firewalls?

I came to know recently IPv4 public IP address pools are going to be exhausted soon. If IPv6 addresses are fully in use, all device vendors like Cisco, Fortinet, Palo Alto have to redesign their ...
user avatar
5 votes
5 answers
800 views

How do two computers with different speeds communicate

This is one extremely basic and probably equally dumb question that I just couldn't ever find a definite answer to. Suppose we have 2 computers one that can transmit data at say 10 bits per second (A)...
php_nub_qq's user avatar
5 votes
2 answers
5k views

Why we use 224 as multicast address in many protocols?

I see in many protocols we use 224 multicast address as like eigrp uses 224.0.0.10 ospf uses 224.0.0.5 224.0.0.6
maddy bhadury's user avatar
5 votes
3 answers
5k views

Why can a host with a single NIC and on two networks have 2 IP adresses?

I understand that an IP adress refers to a NIC and not to a host, therefore a single host can have as many IP adresses as NICs. But Tannenbaum says: It really refers to a network interface, so if ...
Cagu Mumu's user avatar
5 votes
3 answers
5k views

How does Deep Packet Inspection work with encrypted packets?

I've been reading up on Deep Packet Inspection for Software Defined Networks. However, I know that some applications use encryption to evade Deep Packet Inspection. Is there any alternative (such as ...
boomselector's user avatar
5 votes
1 answer
2k views

What are the negative impacts of using non RFC1918 addresses on a private network?

I work for a company overseeing network design of a large industrial system. For our purposes, it's a backbone network that other stakeholders have their own L3VPNs defined on. It is a network with ...
mb_'s user avatar
  • 53
5 votes
3 answers
2k views

Cables on a closed rack

I've just spent the last few days building my first server rack. It will be a significant upgrade to our current mess. I was asked to buy and install one and so I did. I was not completely aware of ...
Dave Cousineau's user avatar
5 votes
2 answers
932 views

Why are there 11 channels in WiFi communication instead of 3?

I'm a little confused about subdividing the WiFi radio band into 11 channels in the USA, 14 in Japan, and 13 in Europe, and to then use just 3 of them because of the overlapping problem. Why didn't ...
zazar's user avatar
  • 63

1
2 3 4 5
17