Questions tagged [networking]

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

Filter by
Sorted by
Tagged with
26
votes
8answers
15k views

Why does DHCP use UDP and not TCP?

DHCP uses UDP as its transport protocol. DHCP messages that a client sends to a server are sent to well-known port 67 (UDP—Bootstrap Protocol and DHCP). DHCP Messages  that a server sends to a client ...
24
votes
7answers
12k views

Why can I traceroute to this IP address, but not ping?

I have an IP address and can traceroute to it, but I can not ping. You see, I can traceroute 43.24.226.50: dele-MBP:~ ll$ traceroute 43.24.226.50 traceroute to 43.24.226.50 (43.24.226.50), 64 hops ...
13
votes
3answers
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.) ...
9
votes
6answers
3k views

Do network adapters read incoming bits in a single stream?

When a Gigabit network adapter is receiving data, how is it receiving the bits? Is it seeing it all in one stream of 0's and 1's? Or is there somehow multiple streams of 0's and 1's coming in at the ...
8
votes
2answers
1k 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-...
8
votes
3answers
4k views

How is tcp/ip implemented

Well, first of all I am new to networking. And I have studied the layered structure of tcp/ip protocol stack. I know that the layered structure is an abstract model, but I didn't know how the ...
6
votes
2answers
1k views

Encapsulation: can a higher protocol encapsulate a lower protocol?

I've heard someone say that a protocol higher up the osi model can encapsulate a lower protocol. As far as I know, personally, a protocol can only encapsulate a same-level protocol or one at a ...
6
votes
2answers
840 views

is there a difference between Latency and speed ?

so latency is the time it takes for bits to get from the sender to the receiver and the speed is how fast bits travel , so logically the more speed the network has the more low latency it has ...
6
votes
2answers
964 views

What precisely is a link?

When reading about layer 2 the word "link" is frequently used but strangely I'm struggling to find a formal definition of it. What is the precise definition of a link? So in the image below, how many ...
5
votes
4answers
199 views

Packet Collison Avoidance

If a wireless network has collision avoidance, how comes the network slows down if more clients connect to it?
5
votes
4answers
6k views

Can anyone explain to me the difference between the PSH and URG flags in TCP segment?

According to me when PSH flag is set, it indicates that data will have to be sent immediately to the wire and on receiving side the data has to be pushed to the application immediately. When URG flag ...
5
votes
2answers
471 views

APIPA and LAN Broadcast Domain

I just want to know can a Local Area Network broadcast domain be operated by only relying on APIPA?
5
votes
3answers
274 views

Are network protocols and routing protocols different things?

When reading about network protocols it says they are a set of rules and format for communication between devices over a network, so basically an agreed way of how to communicate over a network. But ...
4
votes
2answers
2k views

What does it mean to lease an IPv4 block?

When you lease an IPv4 block, what do you actually get? How do you get access to the IP addresses? Is there any special equipment required or is it as simple as renting a server?
4
votes
2answers
301 views

What is the best to simulate an RJ45 cable failure without changing switch configuration or removing the cable?

I am looking at an automation element for a training environment. We would like to be able to fail a cable without doing a shutdown on the interface or having an engineer physically remove the cable ...
4
votes
1answer
105 views

GNS3 switches vs Real switches performance

I want to emulate the performance of switches in GNS3, and the focus is not the configuration of switches. My questions are: Do emulated switches perform worst than actual switches? Are emulated ...
4
votes
2answers
844 views

Juniper SRX answers all ping requests instead of forwarding

I have about 4 different subnetworks at my place, when i'm trying to ping to static device in subnetwork1 from subnetwork2 i always see that device pings, even if it's off. I assume my SRX300 answers ...
4
votes
2answers
61 views

Better throughput with 100 Mb NIC setting

Ran across something very odd today. Just had a symmetrical 100 Mb circuit installed at a site I’m contracting at. When the NIC is set for auto negotiate for duplex and speed, we only get ~96 Mb down ...
4
votes
1answer
310 views

General issues with access to and from DMZ on Cisco ASA 5520

I just got my software upgraded from v8.2(x) to v.9.1(7), but I have some general issues with access to and from my DMZ: No internet access from DMZ No access to web or mail server from outside to ...
4
votes
1answer
49 views

F5 BigIQ communication with BigIP

I'm new to F5. Basically a BigIQ centrally manages BigIP load balancers. In order to update the device, I have to login to the UI and apply the changes there. I would like to know how this is done (...
4
votes
1answer
1k views

What does 'parent interface' mean with respect to VLANs?

I'm trying to learn about VLANs by configuring a router with PFsense installed. Reading the documentation I came across the following sentence: The following example shows how to configure two ...
3
votes
2answers
102 views

Is it possible to limit a IP's traffic in gateway Juniper switch?

In my gateway Juniper Switch: ... irb { unit 0 { family inet; } unit 2 { family inet { address 10.10.10.254/24; } } unit 9 { family ...
3
votes
2answers
165 views

Is it possible to filter directly connected networks redistribute with BGP based on a peer basis?

Assume a simplified case in which router R1 is connected to two BGP peers: one eBGP peer and one iBGP peer. Is there a possibility to advertise directly connected routes only to one of them ...
3
votes
2answers
782 views

How is the term “fabric” defined in networking?

I know this is fundamental and I can find out in Google but so many people differ themselves when they talk about network "fabric". Kindly elaborate on this ?
3
votes
1answer
85 views

How to secure an aging PC from the switch/router side?

I have an aging Windows XP PC whose purpose is to feed code to a manufacturing machine via a RS-232 connection using machine-specific software. The PC needs to retrieve its code from a network file ...
3
votes
2answers
1k views

Connect two routers to a single uplink for full redundancy

I have a single uplink with my ISP at a data center. I have 2 routers (CISCO 3850). How do I connect these routers to that uplink WITHOUT a network switch? That switch will be a single point of ...
3
votes
2answers
74 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 ...
3
votes
1answer
179 views

Cisco Router IOS update

I am facing problem in update the IOS of Cisco 7304 router. I am upgrading from 12.4(24)T2, to 15.2(4)S7 this. but I was boot from this version 15.2(4)S7 it booted proper from flash. But when I put ...
3
votes
1answer
70 views

Why we use transmission system like sonet sdh

Hello friends i have one query that we can connect routers and switches directly on fiber and with high capacity why we uses transmission system like sonet,sdh and dwdm?
3
votes
1answer
413 views

TCP layer behaviour upon receiving wrong sequence number

I have the IP and port details of an already established connection between the TCP server and the client. As I am simulating packet injection attack using the packETH tool, I disguise my self as the ...
3
votes
2answers
727 views

What is the difference between GPON ONU and ONT?

The Optical Network Unit (ONU) and the Optical Network Terminal (ONT) GEEPONs can both connect with an Optical Network Terminal (OLT) via fiber cables in order to achieve an Optical Distributed ...
3
votes
1answer
142 views

ASA 5505 cant access inside network from Anyconnect SSL Connection

So I have a ASA I can connect via SSL perfectly fine receiving internet.My issue is that I cannot ping any device on the network especially the inside network on my router. My topology is a ASA 5505 - ...
3
votes
1answer
515 views

Juniper SRX320 Dynamic VPN, cannot route to Remote-Protected-Resource

Multiple VPNs setup with a Juniper SRX320. The SRX320 has an irb interface as follows: irb { unit 0 { family inet { address 192.168.120.1/24; } } } I've setup ...
3
votes
1answer
2k views

How to connect 192.168.1.x network to 192.168.100.x gateway?

Hello fellow networkers. I am very new to this world and don't know a great deal about IP addresses and subnetting. I however stumbled upon quite a big problem (for me at least - haha) My entire ...
3
votes
2answers
6k views

SSL/TLS belongs to which OSI layer [duplicate]

Can someone please explain SSL/TLS belongs to which OSI layer. I have been looking through many sites and all of them have different options of Application, Presentation and Session.
3
votes
1answer
432 views

Cisco SG300 and Fortigate 90D integration

I need help in setting up my network, currently I have the following setup. All the computers can browse the internet but when I tried to create a two groups (a group that can access the internet and ...
3
votes
0answers
112 views

Can I do Q-in-Q vlans between Dell and Cisco switch

Our Head Office is connected to our DR location between an L2 tunnel provided by our ISP. I need to establish a Q-in-Q setup between both sides to pass multiple VLANs through. Our head office has a ...
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 ...
2
votes
2answers
138 views

Relationship between full duplex and speed

Full-duplex data transmission means that data can be transmitted in both directions on a signal carrier at the same time. but my question is if we have an interface with 100Mb speed and full-duplex ...
2
votes
2answers
557 views

Can a single subnet work across several switches?

New to networking and studying hard but limited access to a kit to try things at the moment... My question is - if I had, for example, two Layer-2 switches cable connected, could I have devices on ...
2
votes
4answers
105 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 ...
2
votes
1answer
63 views

How does a packet find its way from a LAN device to a router, or vice versus?

I am trying to understand how packets are sent from one device to another in a wireless network? (Perhaps the same question also applies to a wired network) How does a router know in which physical ...
2
votes
4answers
63 views

P2P Connections

Hey there I am a noob in the field of networking and I have a confusion: What is the difference between point-to-point and end-to-end connection ?
2
votes
1answer
69 views

Does UDP perform packet re-ordering at the destination?

User Datagram Protocol is a simpler message-based connectionless protocol. Connectionless protocols do not set up a dedicated end-to-end connection. Communication is achieved by transmitting ...
2
votes
1answer
225 views

How do I resolve connection issues between two 10/100Base-Tx to 100Base-Fx fast Ethernet converters

My network at two points, A and B, have the same connection devices that have been working well until recently. A (A is the internet entry point) transmits internet to B (B is the data centre) and B ...
2
votes
2answers
181 views

What defines a “home address”/“home network”? (Computer Networking)

In Computer Networking, and in particular to WiFi-networks, we learn that a "mobile node" (i.e. any mobile unit that can access a router through WiFi) has a permanent IP-address (the "home address"), ...
2
votes
2answers
816 views

what is the difference between cable and dial up modem?

so the dial up modem allows you to access the Internet by converting digital data into analog signals that can travel through the telephone lines , and on the receiving end that modem will ...
2
votes
3answers
303 views

Where does an access network begin and end?

My book's definition for access network is "a network that physically connects an end system to the first router (also known as the "edge router") on a path from the end system to any ...
2
votes
3answers
44 views

What does “terminating incoming connections” mean and what does it imply for network security?

During a recent conversation with a network security team, one of them said: "Look, if that server is terminating incoming connections, it must be in the DMZ." What does it mean to "...
2
votes
1answer
58 views

What are network port maps and what are they used for by the networking team in an organization?

I am curious to know what information generally the port maps contain.

1
2 3 4 5
7