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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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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1 answer
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Trex not receiving any packets

This is my setup to benchmark my server Diagram Trex version v2.88 Trex server MAC ens2f0: f8:f2:1e:5c:bf:78 ens2f1: f8:f2:1e:5c:bf:79 DUT server MAC eth0: fa:16:3e:1c:be:82 eth1: fa:16:3e:d5:37:b1 ...
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4 votes
1 answer
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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 ...
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Beginner Basics; thank you in advance for your time and kind consideration [duplicate]

If PCs connected across the same broadcast domain can send and receive frames based on the MAC address and do not intend to leave the local area network, then why do they need an IP address? Since IP ...
2 votes
3 answers
393 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 ...
1 vote
3 answers
128 views

One client: static IP vs Static lease DHCP vs. DHCP limited range to 1 slot

I want to attach one client (only 1 maximum) to network router ethernet port. I want to always know the client's IP address, for my port forwarding settings. Using DHCP with range the client IP could ...
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1 vote
1 answer
135 views

Why does CLAT in 464XLAT architecture use Stateless NAT64 instead of Stateful?

As of my understanding, stateless NAT is using 1:1 translation, meaning it needs one IPv4 address for one IPv6 address vice versa, thus not preserving IPv4. Since the CLAT is supposed to be router/...
2 votes
3 answers
379 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 "...
1 vote
3 answers
8k views

Difference between Reverse Proxy and Port Forwarding

Well both reverse proxy and port forwarding looks for any incoming packets destined to a particular machine which is present in local network. How both of them are different ?
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1 answer
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Cisco ASA 5516-X won't communicate on inside interface at all. No packets

I'm configuring a brand new ASA and the Firewall refuses to communicate on my inside interface. No matter the traffic type, its denied by implicit deny every time. I was hoping to get some feedback/...
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3 votes
2 answers
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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 ...
1 vote
1 answer
205 views

Does the first TCP FIN packet (active close) goes with just only FIN bit set?

Suppose we have established TCP connection. The active close process assumes the FIN packet been sent to trigger TCP connection closing. But I can't figure out, is this first (active close) FIN packet ...
1 vote
2 answers
69 views

Routing infrastructure doubt. It is a functionally design this?

I have design the following network diagram, but I cannot figure out if it could cause some issue on the network: Some detail about the infrastructure: Network connect Ext rtr A, Int rtr B and C is ...
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1 answer
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Are there broadcast/collision domains on non-Ethernet networks?

What if we have routers or hosts connected via ATM, Frame Relay, or SONET; that is, what if we have IP over SONET, IP over ATM, IP over Frame Relay, etc., do we still have broadcast domains and ...
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1 vote
3 answers
349 views

What kinds of organizations use routing protocols (aside from ISPs)?

I don't understand why would an organization aside from an ISP even use routing protocols. Let's say there is a big company with 5000 employees, and they want to have a network throughout their ...
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1 answer
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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
0 answers
80 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 ...
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1 vote
2 answers
220 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 ...
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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?
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2 answers
226 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. ...
2 votes
2 answers
1k 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 ...
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1 answer
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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 ...
1 vote
2 answers
384 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 ...
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2 answers
2k 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 ...
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1 vote
2 answers
231 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
1 answer
734 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 ...
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1 answer
163 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 ...
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1 answer
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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 ...
1 vote
2 answers
208 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
1 answer
485 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
4 answers
188 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 ...
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1 answer
56 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
1 answer
104 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 ...
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1 answer
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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
1 answer
54 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 ...
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0 votes
2 answers
79 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 ...
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0 votes
1 answer
715 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 ...
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2 answers
114 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?
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0 votes
2 answers
35 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(...
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0 votes
1 answer
167 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 ...
1 vote
3 answers
568 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 ...
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0 votes
1 answer
656 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
6 answers
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 ...
1 vote
1 answer
347 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 ...
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1 answer
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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 ...
1 vote
2 answers
879 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 ...
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0 votes
1 answer
2k 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 ...
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4 answers
573 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
1 answer
1k 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
0 answers
27 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 ...
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