Questions tagged [ipv4]
For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.
755
questions
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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 ...
0
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0answers
12 views
How does IP fragments assembled when identification number field is too small?
Please take reference from this question.
It is said in RFC 6864 that if IP V4 IDs remain unique during MDL, it would limit speed to max 6.4Mbps.
Now high speed devices generate data at a much higher ...
0
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0answers
14 views
How to change IPv4 Address on Public Wi-Fi? [closed]
I have two computers running Windows 10 that are connected to my Hotel's Wi-Fi. I am working on a project that requires both computers to be connected to the same Hotel router, i.e. the "host&...
0
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1answer
24 views
Connecting to device which requires specific IP [closed]
[Disclaimer: I'm a complete networking novice, and this question might not even be well suited for this site. I welcome pointers to other stack exchanges if appropriate.]
I'm trying to connect a ...
0
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0answers
10 views
Why can nodes not communicate on the same network if they're in different subnets? [closed]
Recently, I was tasked as part of a team to build and install a home automation device. Normally, I stay away from the server administration and networking and stick to the coding but I wanted to find ...
0
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1answer
27 views
What are some techniques to infer the subnet being used? [closed]
Given a list of thousands of IPv4 addresses and that you have no direct access to these hosts, is there a service or a methodology to infer a subnet that's possibly being used?
0
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1answer
38 views
Understanding L2 Switch (Network Noob)
I currently have the setup on the left and it works just fine...
I use it to transfer data between laptop and embedded systems hardware device. (Data...Not internet)
Question:
What would the set up on ...
0
votes
1answer
25 views
TCP protocol mystery [closed]
I am attempting to compile, with pcap-filter, the following string:
host yb-in-f91.1e100.n
Obtained from the following command:
netstat -t
output line: tcp 0 0 os-info:portnum yb-in-f91.1e100.n
...
1
vote
2answers
38 views
Is the outgoing interface of a router in the same Subnet as the Incoming interface of the NEXT HOP router?
In the TCP/IP Volume 1, it is stated that ARP works only on the same subnet. Does this mean that the outgoing interface of a router is necessarily on the same subnet as the incoming interface of the ...
1
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2answers
26 views
What is the need for the NEXT HOP coloumn in the routing table when we already mention the OUTGOING INTERFACE in another coloumn?
If the OUTGOING INTERFACE is already mentioned in the routing table, it is natural that the next hop will necessarily be the router attached to the outgoing interface. Then why is there a separate ...
-1
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1answer
29 views
different network mask and subnet mask and netmask [duplicate]
1- what is network mask?
2- what is subnet mask?
is there any differnt between network mask and subnet mask?
i'm tried to search about network mask and nothing found is it called netmask ?
thank you
0
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3answers
58 views
Private IP Address Subnetting Standards. How strict are they today?
How strict is this standard today.
The 172.16.0.0/12 range is: 172.16.0.0 – 172.31.255.255
Conceptual Config
172.Location.VLAN.Host
Location A (10):
VLAN 10 - 172.10.10.0/24
VLAN 20 - 172.10.20.0/...
0
votes
2answers
53 views
Possible typo in Tanenbaum's book about NAPT
From what I have understood from multiple sources (web and other books) about the concept of NAPT (also called NAT overload or IP masquerading in Linux environment), if there is a scenario like the ...
2
votes
1answer
70 views
what were the classless routing protocols used with VLSM when it was first introduced?
Since VSLM is supported only by classless routing protocols, if VSLM was introduced in 1987(RFC 1009) and all classless protocol(RIPv2 developed in 1993 , OSPF standardized in 1989 RFC 1131 ) cited ...
0
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2answers
283 views
Is TCP's MSL value equivalent to IP's TTL value?
Definition of MSL according to RFC 793:
Maximum Segment Lifetime, the time a TCP segment can exist in the internetwork system. Arbitrarily defined to be 2 minutes.
Definition of TTL according to ...
2
votes
1answer
51 views
Why can my device not get an ip from DHCP in a network with 2 VLANS of which one has DHCP?
In our company we have a CISCO 2811 Switch accompanied by an HP1920 Switch. Our current configuration consists of 2 VLANS:
VLAN-2 that has no DHCP in IP range 192.168.0.0/24
VLAN-5 That contains DHCP ...
0
votes
1answer
34 views
Hi! What does it mean if at the same time, two external IP addresses are identical except the last set of numbers, like 123.1.12.16 and 123.1.12.213? [duplicate]
The IP addresses are of two users that are logged in at the same website at the same time. Does this mean the users are on different routers but at the same location or on the same intranet?
0
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1answer
26 views
Is the OPTIONS field included in IP checksum calculation?
The source host wants to estimate the time it takes for the datagram to go from one router to another. Therefore, the router uses the timestamp option in IP with Timestamp Flag = 1.
I am confused as ...
0
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2answers
61 views
Can a Core Switch detect a duplicate IPv4 for two computers not directly connected to it?
I have a Core Switch (routing capability) connected to two access switches. Each switch has a computer connected to it with the same IP and same VLAN. The Core Switch operates as a Level 3 device. All ...
0
votes
2answers
32 views
why ip protocol use fragment offset instead of index number?
I was wondering why the IP protocol use fragment offset to define the fragments of an IP datagram instead of using index number (first fragment with index 0, second with index 1, ...). We already know ...
0
votes
2answers
44 views
Can a host from different subnet bypass the network mask validation of destination host and communicate on layer 2?
I am aware that a host will always check the subnet of the destination node before the transmission in order known if it has to send it to the gatewey for different subnet.
However, would it be ...
0
votes
1answer
24 views
Understanding IP scheme, distribution and usage [duplicate]
I'm new to networking and I'm doing my best to understand how things work. I do have a problem in understanding IP scheme idea (even though obsolete), more specifically, their structure, distribution ...
0
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0answers
9 views
How to calculate the prefix of an IP Address? [duplicate]
I know there are many questions/answers for this already but i'm really confused on how the prefix of an IP is calculated. I'm currently doing an mock paper for an exam and the question goes like this:...
0
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1answer
27 views
How can I assign a static public ip to a machine behind a router?
I know about port-forwarding, but I'm interested in how to make a machine on a local network available to the public internet without port-forwarding.
0
votes
1answer
27 views
Default subnet question [duplicate]
Very new to network engineering. I just watched a really good series of videos on YouTube explaining IP addresses, subnet masks and the class system for IPv4.
There was one bit which got me confused ...
24
votes
3answers
6k views
Will IPv6 make private IP addresses become obsolete?
Will it still be useful to make use of private IP addresses with IPv6?
0
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1answer
63 views
I don't understand IP addressing for a router
I am taking an internet (CISCO) course and don't understand the difference between the default gateway address for a router and its IP address. In every example of the class the default gateway ...
0
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0answers
11 views
Determine the range of IP's avaliable for hosts on a subnet /28 [duplicate]
I am looking into my Virtual Switch configuration( Hyper-V ) and i am confused how the range of valid IP's is determined.
The IP for configured for the "Virtual Switch" adapter is:
IP: 192.168.53.65 ...
2
votes
2answers
206 views
transferring IPv4 /32 to another datacenter
We are planning to migrate one set of IPv4 /32 series owned by us, from one dedicated server provider to another provider. Is it necessary to have permission to release the IP series from previous ...
1
vote
0answers
29 views
If a server has both IPv4 and IPv6 addresses, how does the DNS determine which to return? See the following example [closed]
These Pings were done at different times of the same day:
C:\Users\LPress>ping www.ucla.edu
Pinging gateway.lb.it.ucla.edu [164.67.228.152] with 32 bytes of data:
C:\Users\LPress>ping www.ucla.edu
...
4
votes
4answers
375 views
Layering unicast addressing over multicasts
My question has to do with layering of unicast over multicast and has two parts.
Part 1. IP unicast over MAC multicast
First part of the question is whether there is a standard that prohibits use of ...
-1
votes
1answer
43 views
Able to ping Domain internal address on home network, why? [closed]
I have a strange issue, I am able to ping my company's internal address (ex: hq.mycomapny.com) when I am on my Home network (WI-FI or Enthernet) and NOT connected to the VPN.
When I do a ping on the ...
0
votes
0answers
18 views
Are network IP addresses ever used as source or destination IPs? [duplicate]
The first IP address of an IP subnet is the network address, which stands for the whole network, while the last address is the broadcast address.
As far as I understand, we never really send packets ...
1
vote
1answer
68 views
IPv4 maximum datagram size
The IPv4 datagram consists of two parts:the header length and the payload. The maximum header size is 60 bytes and minimum is 20 bytes. The maximum size of the data can be 65515 bytes. So why the ...
1
vote
1answer
146 views
Broadcasting to unknown Class C Network
I am trying to use python to broadcast to my local network, and I cannot find a way to get the subnet mask. I have been suggested to use the default Class C network subnet mask 255.255.255.0, and use ...
1
vote
2answers
46 views
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 ...
0
votes
1answer
39 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....
2
votes
1answer
78 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 ...
0
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0answers
19 views
How to find minimum of hosts bits needed and assign equally to five subnets? [duplicate]
I have a 192.168.1.0/18 network block. How do I determine the minimum number of host bits to be borrowed and assigned equally to five subnets? How to calculate the number of users that can be ...
2
votes
2answers
56 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 ...
0
votes
2answers
58 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 ...
0
votes
2answers
225 views
Routing Table Settings To Access An Internal Network Through VPN [closed]
I have a remote computer behind a VPN (which I have no control of). The IT team of the remote factory wanted me to install Palo Alto Networks' Global Protect program to access the VPN, which is ...
0
votes
1answer
98 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 ...
0
votes
2answers
61 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 ...
2
votes
1answer
48 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 ...
0
votes
2answers
60 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
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 ...
1
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0answers
37 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 ...
1
vote
2answers
467 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 ...
1
vote
1answer
42 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 ...
1
vote
2answers
96 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 ...
