Questions tagged [ipv4]
For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.
834
questions
1
vote
2
answers
46
views
What should we do if the number of bytes to be transferred are not in multiples of eight in ipv4? [duplicate]
(it is take from book called special edition tcp ip, pic taken for better formatting and ease to read)
Theory that I am trying to understand-:
So i found a question that is relevant to this-:
->a ...
- 21
1
vote
1
answer
19
views
How is 65535 bytes is total length of IP datagram?
The maximum size of an IPv4 packet is 65,535 because the Total Length field is a 16-bit unsigned integer, which has a possible 65,536 values (from 0 to 65,535).
This created 2 confusions for me.
Say ...
- 21
0
votes
2
answers
25
views
How to use IP pool
I am just beginner, I just want to setup my mini data center and for testing i get a FTTH connection and /30 ip pool, ISP reply is something like that, "IP Pool 103.15.xx.xx/30 has been assigned ...
0
votes
0
answers
9
views
How can i find device type and name in linux terminal without install nmap and other similar tools from it ip address? [closed]
I'm looking for find a way to get device name and type like ESET Connected Home Monitor .
Eset :
Connected Home Monitor can help identify vulnerabilities in your home network such as open ports or a ...
1
vote
2
answers
79
views
Why shortened version of IP4 exists and it is undocumented but supported everywhere?
For example there is an IP address 192.168.0.1
It is clear that you can use it as the full line, but try that one 192.168.1
It will also work, and it will be automatically converted to 192.168.0.1
...
- 113
0
votes
1
answer
14
views
DHCP Discover Broadcast and its IP (255.255.255) [duplicate]
Cheers, I am trying to learn more about DHCP, and when studying about the session that DHCP goes through every one mentions that it broadcasts a discover message at IP: (255.255.255.255) (as seen here ...
0
votes
1
answer
60
views
VLAN routing on the same subnet
Consider following situation:
You have 10.3.0.0/16 network without any VLANs. Now You want to divide it...
You want Your IT department be able to reach the entire network, but sales department only ...
- 3
0
votes
0
answers
17
views
Why does a router need 2 IP address? [duplicate]
Suppose there are 2 PC and 1 router in "LAN1", now if PC1 wants to communicate with PC2, it will need to uniquely identify PC2. So, PC2 gets a private IP that no other PC in LAN1 will have.
...
0
votes
0
answers
7
views
Dividing network into subnets [duplicate]
My teacher uploaded this example question and solution as explanation of the topic:
I watched some videos about it but none of them made it fully clear, what I don't understand here is:
What are ...
-1
votes
1
answer
29
views
How are there still enough public IP addresses? [duplicate]
If I understand correctly, a NAT is a translation from your private IP to a public IP because there are not enough public IPv4 addresses. This way multiple devices across one network with private IPs ...
- 1
4
votes
1
answer
70
views
How Can a VPC ping the Router through an Etherswitch that behaves in one port as router and in the other as switch
In the following topology my main purpose is to:
1)PC11 ping Router(R)
2)PC11 ping PC13
ESW10:
In gig0/3 has the no switchport command and a given IP address.
In gig0/2 it has the switchport access ...
- 89
1
vote
1
answer
39
views
How does providing IPv4 occur through mobile internet?
I've read that there are 2 types of IPv4 addresses: public ip-address and private ip-address.
Public ip is used to connect devices to the internet (WAN). There's always an example about routers that ...
- 113
2
votes
1
answer
60
views
Custom option in IP header
I would like to add (or piggyback on an existing not used) a custom option to the IP header. I've full control of the IP stack at both end points, but I've no control on all the hops in the route (...
- 123
0
votes
3
answers
47
views
why ip adresses are divided into network portion and host portion when we already have NAT [duplicate]
I don't understand why ip adresses are divided into network portion and host portion? is the host portion really necessary when we already have NAT?
for example, if ip addresses only have network ...
- 101
0
votes
1
answer
37
views
Fragments taking different routes?
I have trouble understanding why sometimes it occurs that during IP fragmentation certain fragments take different routes. I was following this the second example:
https://www.gatevidyalay.com/ip-...
- 1
1
vote
1
answer
65
views
Understand DSCP and Precedence Values in Ipv4 or Ipv6 packet
I read from this website to understand DSCP and it's corresponding IP precedence value.
For example DSCP value is '000 000' which Drop Probability is N/A(never happen) and it's Equivalent IP ...
- 346
0
votes
1
answer
16
views
Does socket address include transport protocol (http://)? [closed]
Let's say I have the following: http://ip_addr:port
This is supposedly called the socket address (see sources below), but I can't find a conclusive answer anywhere if the transport protocol (http://) ...
0
votes
1
answer
19
views
Enquiries regarding securing strong password and ssh
I am a beginner in computer network and I have done some research with regards on how to do IP configuration on PC and routers. However, I am not sure on how to configure strong password and ssh based ...
- 1
0
votes
1
answer
56
views
Why would we want to subnet/change CIDR of private addresses?
I am studying for my CCNA and my current topic is subnetting.
I understand how subnetting works and how to subnet (calculate the network IP, the amount of hosts, broadcast, etc). However, I can't seem ...
- 173
0
votes
0
answers
10
views
Subnetting and dividing networks [duplicate]
I am currently learning about how subnetting works and I need to get rid of some confusion.
If we divide networks like this, and assign each network a different IP address (192.168.1.0, 192.168.2.0, ...
- 173
9
votes
6
answers
2k
views
Is CIDR IP format currently in use?
I'm reading a book that says that, historically, there have been three ways to interpret IP addresses:
Classful
Subnetting with subnet masks
Classless Inter-Domain Routing(CIDR), supernetting.
My ...
- 91
0
votes
0
answers
10
views
What is the routing prefix (in format: address of a network/bit-length of the prefix) for the smallest subnet that contains these four hosts? [duplicate]
A computer network has hosts with the following IP addresses:
124.127.64.147
124.127.64.151
124.127.64.155
124.127.64.156
What is the routing prefix (in format: address of a network/bit-length of the ...
2
votes
1
answer
64
views
Which ranges of IPv6 and IPv4 do requests to the local network and the host?
I'm looking for the range of IP address that is bound to the local network or the host itself.
So far for IPv4 I found:
10.0.0.0 - 10.255.255.255
172.16.0.0 - 172.31.255.255
192.168.0.0 - 192.168.255....
- 23
0
votes
0
answers
17
views
Subnetting an network into different number of subnets [duplicate]
Assuming you are using a Class C IP address (195.16.1.0) and you need to create the following numbers of subnets for your network plan. For each of the numbers of required subnets below, provide how ...
1
vote
1
answer
24
views
Does a Transparent Firewall need a Default gateway if directly connected to a layer 3 device that is actively performing routing?
Good folks of the Network Engineering stack!
I have a question that I assume most people could answer in their sleep. To better illustrate my question, I've provided a sketch of my network below.
In ...
- 13
1
vote
1
answer
47
views
Can I set fragmented IPv4 packet's DF bit to '1'? [duplicate]
If make DF to 1, can I confirm that fragmented packet with DF=1 will go through routers to the dest IP without any reassembly and re-fragmentation?
- 11
0
votes
2
answers
113
views
Could we use private IP address as directed broadcast address?
We know that private IP addresses ranges of class A, class B, class C are 10.0.0.0-10.0.0.255, 172.16.0.0-172.16.255.255, 192.168.0.0-192.168.255.255 respectively.
My first questions is that first and ...
- 346
-1
votes
1
answer
39
views
How can someone connect to my computer even through port forwarding?
If I set port forwarding up on my router to redirect connections on port, say, 50000 to my computer, how can someone connect to my router in the first place ?
Does that mean that my router has a ...
1
vote
2
answers
59
views
How can I use scapy to make a port appear open-device behind NAT?
This has been asked in stack overflow like 7 years back. I don't see the correct answer there. Is there any way to do this?
While this packet keeps on being transmitting, doesn't the other end see the ...
0
votes
1
answer
83
views
Duplicate IP addresses on different "levels" of subnets
My question is quite simple: let us say there is a 10.0.0.0/8 with the subnet mask of 255.0.0.0 (first 8 bits used up for network address).
Let us say, one address in our subnet is 10.0.0.1 (subnet ...
- 133
0
votes
1
answer
55
views
What is the reason behind not returning unused IP addresses? [closed]
There are several companies out there with one or more /8 IP addresses, for example:
DoD has more than 200 million,
HP has one /8 (>16 million),
Apple has one /8,
General Electric has one /8,
IBM ...
- 103
1
vote
5
answers
270
views
What happens to the unused IP addresses in the subnet that falls in between two routers?
This is probably a un-realistic question, but a question nonetheless, that has been bugging me since quite a while now.
Consider the below network diagram, where R1 is a part of a 10.0.0.0/8 network (...
- 133
1
vote
2
answers
460
views
What is the minimum MTU of IPv4 68 bytes or 576 bytes?
I read that 68 bytes is the minimum size of IPv4 datagram every device must be able to forward without further fragmentation.
576 bytes is the minimum size of IPv4 datagram every device has to be able ...
user80210
2
votes
1
answer
883
views
Which one is right, UDP has 508 or 512 bytes payload limits?
We know the size guarantees the datagram won't be fragmented in IPv4 is maximum 576 bytes. But the size when use UDP header 8 bytes and if we take UDP payload 512 bytes and choose maximum header size ...
- 346
0
votes
2
answers
70
views
network IP packet format
i completely understand that why receiver there is 576 bytes but my question is as technology update every after one Minutes then why we can't update that limit
[enter link description here][1]
0
votes
1
answer
45
views
Do IPv6 addresses have better persistence with DHCPv6?
I have a LAN with about 25 devices that occasionally grab each other's IP address via DHCPv4. I know there are certain lease time limits and it can be set to very long periods to work it around to an ...
- 103
1
vote
1
answer
104
views
Are IPv4 type of service and IPv6 traffic class equivalent to each other or is traffic class IPv6 specific? [duplicate]
IPv6 has a traffic class field. According to the specification it is an IPv6 length, out of which first 6 bits are called code point or differential services code point (DSCP) and the last 2 bits are ...
- 346
0
votes
1
answer
205
views
How to tell if an ipv4 address is public or private?
I've read the below thing, in a website.
According to standards set forth in Internet Engineering Task Force
(IETF) document RFC-1918 , the following IPv4 address ranges are
reserved by the IANA for ...
- 97
-1
votes
1
answer
118
views
Why the pseudo-header is not transmitted with the UDP datagram?
I have read from E. Comer - Internetworking with TCP/IP 4th edition that "The purpose of using a pseudo-header is to verify that the UDP datagram has reached its correct destination. The key to ...
- 346
0
votes
1
answer
235
views
UDP checksum calculation for checksum results in the value zero
I read UDP checksum from Wikipedia that "If the checksum calculation results in the value zero (all 16 bits 0) it should be sent as the one's complement (all 1s) as a zero-value checksum ...
- 346
0
votes
1
answer
160
views
Why UDP checksum is optional for IPv4?
We know that IPv4 header has checksum for header not for data .Therefore for checking data error we need checksum in transport layer. Suppose we're using UDP in layer 4. So if I remove the checksum ...
- 346
0
votes
1
answer
75
views
How UDP checksum get IP address to make pseudo header in transport layer?
We know that UDP checksum's pseudo header contains the most important parts of the IP header, that is, source and destination address, protocol number and data length.
I hope that the concept of IP ...
- 346
0
votes
1
answer
67
views
SNMPv2 to v3 conversion
Can I use a Cisco router to convert SNMPv2 from an end device in one network to SNMPv3 and the C&M software in another network?
The end device can only handle SNMPv2, but the C&M community is ...
- 583
0
votes
2
answers
295
views
Is it possible for TCP can accept out of order segments?
TCP is connection-oriented protocol whereas IP isn't connection-oriented protocol. Any packets before sending into transport layer sorted operation must have been done in network layer. That's why we ...
- 346
1
vote
2
answers
43
views
Do routers overwrite options of IP packets?
If i use IP options to send secret messages outside of the network using for example EIP, will the router replace them before sending out to the internet?
- 11
3
votes
2
answers
282
views
Why can IPv4 and IPv6 use strict source routing(in options field) and flow label respectively inspite of connectionless protocol?
In IPv4 option field one field option is source routing option this means packet will always be routed by router Or not. Packet can also be routed by source such routing is known as source routing. ...
- 346
-3
votes
1
answer
72
views
Does IPv4 of all devices follow this standard xxx.xxx.x.x?
I think the title says it all. I haven't found the answer anywhere else on the internet.
- 11
1
vote
2
answers
52
views
Ping a host on the same network with special IP 0.0.0.0/8
I am trying to ping the host 192.168.1.5 from my computer.
This works good.
The subnet mask of the IP is 255.255.255.0, so the private IP 0.0.0.5 can also be used to ping the same host. But that ...
0
votes
2
answers
196
views
Class D network for multicasting between group
We know Multicasting is defined as a single source sending to multiple recipients on a network when the receiver broadcasts a signal for acceptance. Multicasting has its own Class D IP addressing ...
- 346
1
vote
2
answers
52
views
Can I assign one of my publicly available IP address to my AWS instance?
I would like to be able to use one of my publicly accessible ip addresses directly with my aws cloud instance. Is there a way I can assign or transfer one of my ip address to aws? My ARIN registry ...
- 13