Questions tagged [ipv4]

For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.

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Where are broadcast packages filtered out

When I have one network with a switch. Within that network I have 10 PC. Halve of them are configured within the 192.168.1.0/24 range and the other halve is configured at 192.168.2.0/24. This means I ...
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1answer
40 views

Find Routes not containing these subnets [closed]

Let's say I have 1000 ranges and I would like to make routes that doesn't match these ranges, anyone has any particular tips or tools to share beside doing math ? Example : I have these ranges 13....
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1answer
396 views

Why Classful addressing is not in use if we can subnet them?

So, Let's think that organization needs 5000 IP addresses. Giving 20 C Class IP addresses will cause of adding 20 entries for ISP router. That's problem. We could give Class B IP address, but that ...
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2answers
111 views

The MSB of IPv4 flags

In IPv4 header, there is 3 bits field called "flags". The MSB of this field must be reset to zero (as many networking blogs say without telling why). i want to know what will happen if I managed to ...
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3answers
106 views

Do NAT devices need to have private IP addresses?

If a NAT's job is to create mappings between internal ip/port pairs and external ip/port pairs with one Internet-routable IP address, does a NAT need a private IP address for itself? I think one ...
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2answers
541 views

Can I run 2 separate ranges on the same physical network

My current set up is 1 router and 2 switches, the router being 192.168.10.1 with a connection to each switch then 8 and 10 devices on the 2 switches all 192.168.10.x I have an NVR with 2 ports, 1 of ...
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83 views

When a packet is received, how does it know which internal machine to send it to?

I am familiar with ARP and routing, but I think I am failing to put two and two together here. On an IPv4 packet we have the source IP address, which allows any router to send the response back to the ...
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1answer
136 views

Is an IP broadcast always a layer 2 broadcast also

On my PC I see 255.255.255.255 in ARP with MAC FF:FF:FF:FF:FF:FF, so I'm assuming that in most cases the L3 broadcast is also encapsulated into an L2 broadcast frame, but is this standardized? For a ...
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2answers
105 views

Why can some people use public ip address to access a server from an internal network with the client device within the internal network [duplicate]

As the title suggests. I find it mind breaking to think how network architecture can differ to allow/not allow using public IP address to access a server within internal network from within the ...
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1answer
173 views

How can I configure a Cisco router 4300 to allow internal server ip:80 to be accessed on public ip:4500

I have an internal web server on port 80. I need help commands maybe to configure port forwarding to access the server on my private network from a public IP Current running config interface ...
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2answers
880 views

MTU the most Confusing Networking term. Lot of questions

I have ton of questions and i feel this is most confusing term for me. The more i read the confusion deepens. I am not able to connect dots. please help. Do we need MTU adjustment with EoMPLS/dot1q ...
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1answer
48 views

IPv4 Subnetting for 1200 or more devices for WiFi

I am currently looking over my schools existing Subnets and their usage. Some seem to be sufficent, others not so much. What is the best practice when you need to support 1200 or more devices on a ...
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2answers
222 views

Question about the destination IP inside an IPv4 packet

I'm reading about link and network layers for the first time and I'm trying to put the pieces together to understand how they work together. My question may not have to do with the link layer but I'm ...
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5answers
17k views

Usage of 192.168.xxx, 172.xxx and 10.xxx in private networks

I know that the organization that distributes IP addresses decided to assign 192.168.xxx, 172.xxx and 10.xxx to private networks. However, I thought that private networks have their own address space ...
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0answers
58 views

Is it possible to access 127.0.0.xxx in anyway [closed]

So I've been configuring my network at work. We've got a lot of devices from NAS servers to Dante AoIP devices. While configuring some of my devices I managed to set the IP adress of one device to ...
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3answers
3k views

Does NAT violate end to end argument?

Does NAT violate end to end argument? What does end to end argument means in this context?
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0answers
76 views

How is it possible to have a default gateway outside of the network range of any interface? [closed]

I always thought that the default gateways has to be on the same network as the server/client trying to connect to the internet. However today I rented a server from Hetzner and the server is able to ...
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1answer
850 views

Remotely Connecting an IPv6 Computer to a IPv6 Private Web Server

I have a private web server at my office, and I want to access that server remotely at my house via IPv6. My office has both IPv4 and IPv6 enabled, but my home has only IPv6. IPv4 works, but I have ...
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2answers
656 views

Loopback with / 32

When we dealing with bgp, osp. Why do we especially use loopback interfaces with / 32!? Is there an advantage or something different from other subnets like 24.
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1answer
46 views

Setting the network address freely [duplicate]

I'm trying to understand IP Addressing, but there's something what's still not clear for me. With mask 1111111.1111111.1111111.00000000 (/24) Am I able to set network address "freely" like this? ...
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1answer
137 views

Next Header field in IPv6 vs Protocol field in IPv4, any difference?

So I am new to the IPv6 concept, and I seen that the Protocol field seems to be replaced with Next Header, and I have a question. Question: Is Next Header a complete replace of Protocol, or is they ...
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3answers
151 views

What is the intuition behind subnetting a base IP?

Take a look at this picture: My professor usually gives a topology like this and gives me a base IP. Let's say the base IP given is: 223.1.0.0/24. We're then asked to construct the given topology by ...
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1answer
112 views

Confusion about IANA "Protocol Numbers" registery

In the IANA registery for "Protocol Numbers", there listed 2 IP protocol versions: IPv4 at #4 and IPv6 at #41. Their "protocol" column says IPv[46] Encapsulation, and "...
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3answers
525 views

Will pinging the multicast "all hosts" IP 224.0.0.1 fill my ARP cache with all hosts on my current subnet?

Just wondering in case I ever have a want / need to see all the hosts on my subnet.
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1answer
273 views

Typical signs of fragmented IP fragments

Given, for example, a Wireshark trace, how can I identify that the IP fragments that I am sending are themselves being fragmented? For example, if I'm sending 1500 byte IP fragments, and the server ...
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1answer
319 views

How does NAT ensure that every machine has a unique public IP?

I am trying to understand the distinction between public and private IP addresses in IPv4 networking. The picture I've been told has some problems with it, so I would like to present it here and ask ...
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4answers
6k views

Why is 10.1.255.255 an invalid broadcast address?

I’ve been following the CCENT official certification book(100-105) and came upon this question in the “do I know this already?” quiz. The books only covered /24 subnetting only so far. Which of the ...
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1answer
482 views

Can communication to broadcast 224.0.0.1 be made to reach hosts outside of the local subnet?

I been asked the question if it is possible for an a IP host to use multicast to address 224.0.0.1 in order to reach (and get a response from) another host which is not on the local network segment ...
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1answer
316 views

When IP header of length 22bytes is there then how padding will work?

My base IPv4 header of 20bytes + 2bytes i used for Options making it 22bytes means 176bits so padding will add 16 Zeroes to make it multiple of 32? is this correct way to understand? Boundary of ...
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1answer
207 views

Which IPv4 options must be copied on fragmentation and why?

In RFC 791 page 14 it says The copied flag indicates that this option is copied into all fragments on fragmentation. 0 = not copied 1 = copied If I understand correctly it is possible to specify ...
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2answers
4k views

What's the DF flag mean in IP packet header?

In the IP package, there is DF flag: Don't Fragment. I have doubt about it, is it mean let all the L3 device do not to fragment the IP packet (if the L3 device found it is bigger than MTU, device ...
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2answers
64 views

Can 2 Directly connected PCs having the same network ID but different subnet mask talk? [duplicate]

If Pc1 has IP 192.168.10.2 / 24 ---> Network ID : 192.168.10.0 and Pc2 has IP 192.168.11.3 / 23 ---> Network ID : 192.168.10.0 directly connected (no switches no routers). Why cant i ping? But if ...
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1answer
75 views

Floating Number representation for Ipv4 address

I'm wondering if we can have floating point(3.3 9.9 2.2 6.3) or Hexadecimal(6A.65.D5.77) representation for Ipv4 address that is also 32 bit long to compensate for IPv4 address shortage. Same ...
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1answer
3k views

Why the IPv4 need Don't fragment Flag?

Why the IPv4 need Don't fragment Flag? We know the IPv4 Flags options are: Reserved bit, Don't fragment, More fragments, fragment offset options. Why there need the Don't fragment Flag? if it is ...
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1answer
564 views

How to understand the Flags is IP_MF, what will happen?

For data packets whose length exceeds the MTU of the interface, fragmentation processing is required. The fields related to fragmentation in the IP header are as follows: Identification - Used to ...
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4answers
1k views

How do devices connected to a switch get their IPs?

It should go without saying, I'm new and still learning about networking. One of the things I'm not clear on and couldn't find a satisfying answer to, although I've done some digging around, is how ...
3
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2answers
228 views

Global BGP Routing only by only importing supernet prefixes

I was wondering if global IPv4 Routing can be technically achieved only by importing from the ISP Provider (providing us with a IPv4 BGP full table) a subset from the BGPv4 routes (i.e. all prefixes ...
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2answers
459 views

What information does the network and host components of an IP address indicate?

I understand that an IPv4 address is represented by 4 consecutive bytes: <8bits>.<8bts>.<8bits>.<8bits> And understand that this 32bit address comprises a 'host' and a '...
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2answers
1k views

Why do transport layer do data chunking. If there is fragmentation in Network Layer

I just curiously wanted to know about the question regarding L4, L3 Data Chunks, IP Fragmentation : Data chunking happened at Layer 4(Transport, TCP), and Fragmentation at Layer 3(Network, ipv4) ...
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2answers
830 views

What determines the private ip addresses? [closed]

Right now, I am using internet at home, and my private ip address is 192.168.x.x. At work my private ip address is 10.x.x.x. In both of the scenarios, I did not play any role in selecting my ip, I ...
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1answer
192 views

Scaling fragment offset

I studied that fragment offset has 13 bits. At transport layer segmentation is done considering the the MTU at lower layers (network layer, data link layer). Ethernet format says the maximum data ...
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1answer
698 views

Prevent Users from Setting Specific Static IP

I have an HP procurve switching environment in which users are often assigned static IP's. One user changed their IP to 172.17.1.1 which is the core switch VLAN 10 interface. Since all the users in ...
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1answer
76 views

Bringing two different hosts each in two different subnets into a same subnet [duplicate]

Physical Network: 11.11.10.0(mask:255.255.248) Subnet A 1 :11.11.10.0 IP A: 11.11.10.4 (mask:255.255.248 and 6 hosts) Subnet B 2 :11.11.10.8 IP B: 11.11.10.11(mask:255.255.248 and 6 hosts) Hi ...
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2answers
100 views

Meaningless bits in CIDR notation

Is specifying meaningless bits valid syntax in CIDR notation? For instance, the netmask of 192.168.13.0/16 is 255.255.0.0. In this case, the last two octets (00001101 00000000) are meaningless because ...
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2answers
4k views

Why does yealink ip phone is not getting ip address from voice vlan?

I have configured separate vlan for voip and connected interface to it (as shown below). But the phone is not getting ip address automatically. switch- cisco 2960-x phone- yealink I had tried: (on ...
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3answers
196 views

Why can my ISP use 172.39.29.71 as local network IP? [closed]

I just check my IP routing? and it turns to be: IP:10.29.66.27 -> 172.39.29.71 -> x.x.x.x my outmost IP, which I get by Google "my ip". As far as I know, 172.16.0.0/12 is the one of the 3 private ...
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3answers
90 views

Sending an ipv4 packet to the Destination IP without a router?

We are replacing a "RF modem + Router system" with a Software Defined Receiver. After analyzing the receiving and sent signals we found out that an IPv4 UDP packets have been sent and received. The ...
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1answer
70 views

What do you need apart from registering IP addresses to use them?

I need to connect to a certain Site from several public IP addresses (~1 million). Assume that I am Bruce Wayne so I could spend several million dollars on this. The site at least for now is not IPv6 ...
2
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1answer
75 views

Is this possible (NAT??)

I have a device on another network, say it's IP is 10.1.1.1 I want to ping it from my own network, say host 192.168.1.1, but I want to ping an address in my local segment to do so,so 192.168.1.2. Is ...
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1answer
93 views

Assign a new public and static IP to a router behind my main router [closed]

What can you suggest to bring a second public and static IPv4 so I can configure my WAN-A interfase with my primary and an additional secondary IP settings so I can route all the traffic from the ...

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