Questions tagged [ipv4]
For questions about Internet Protocol version 4 (IPv4); as specified in RFC791.
771
questions
0
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1answer
12 views
Loopback interfaces subnets [closed]
Assuming that loopback interface is always alone in its network, what are the practical reasons to have IPv4 subnet prefix shorter than /32 for these interfaces?
Moreover, why according to various ...
2
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3answers
63 views
Routing with private addresses
Let's say that we have a private network, with private addresses and a NAT enabled router at the end. If the router is misconfigured and routes traffic to the global internet, keeping as source ...
1
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3answers
71 views
Combining NAT an tunneling
I was reading a text and a doubt came to mind. Suppose there is an interface in a router that implements NAT. That same interface is the extreme of a tunnel. If I was to send a message through said ...
1
vote
1answer
23 views
“SWIP” Equivalent for RIPE?
With ARIN, I was familiar with using "SWIP" for IP blocks via an ORG and a POC.
With RIPE, however, it seems that it's different.
I have access to a RIPE account where I can make the changes,...
1
vote
3answers
39 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 ...
-1
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0answers
9 views
Please solve this question [duplicate]
b) An organization is granted the block 211.17.180.0/24. The administrator wants to create 32 subnets.
i. Find the subnet mask.
ii. Find the number of addresses in each subnet.
iii. Find the first ...
0
votes
2answers
51 views
Is the routing table used when sending IP packets to a host on the same LAN in ipv4?
I am having trouble understanding the steps in order to send an ip packet to another host on the same LAN. Most sources online that I have read and people I have talked to say that the host uses the ...
1
vote
1answer
32 views
By General Convention if we say the Frame size is 1KB do we take it as a 2^10 Bytes or 10^3 Bytes
In my academic we generally follow 2^10 Byte approach , I m really at loss is it by convention only at my college or something which is accepted widely
0
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2answers
385 views
Is not 192.168.88.1 (192.168.*.*) always an “internal” IP address?
I had some headache with a proxy setup which I couldn't figure out. Turns out that only "127.0.0.1" and "localhost" were recognized as "localhost" or "internal" ...
0
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1answer
85 views
How to find the first and last address in the FIRST AND LAST SUBNET [duplicate]
So there's a problem that literally stress me out every time I look at it. It's like I almost understand it until I get to knowing how to find the first and last host in the LAST address (last subnet)....
0
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1answer
23 views
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 ...
2
votes
1answer
58 views
IPv4 and UDP/TCP packets inside of ICMP packet?
A week ago, after opening wireshark, i was surprised by seing a storm of ICMP packets from different IP addresses. While deep analysing of thoses packets, i noticed that those ICMP packets contains ...
-1
votes
1answer
40 views
IPv4 and IPv6 Source Address field
Both the IPv4 and IPv6 headers contain the source address field.
What are the reasons for including this field?
Is it for to trace which who sent this packet if it get's lost?
0
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0answers
12 views
How does the IPv4 Total Header Length field & Fragmentation work together? [duplicate]
I recently learnt that the maximum value of the IPv4 Total Header Length field is 65,535 which equals approx. 65.5KB. To my understanding, it is different from the IHL field as it includes the ...
0
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0answers
11 views
Why does sub-netting not give us more addresses? [duplicate]
Sorry if this is dumb, but I am very knew to learning about networks.
Here is my reasoning?
Let's take the address, 24.50.12.4
if we subnet it with /16 then the network address is 24.50 + host is 0.0....
0
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0answers
9 views
How to find Best Fit Mask [duplicate]
How does i find the best fit netmask (i.e., resulting in as few host addresses as possible) for a
network with 62 hosts in it?
I don't have any class like A,B,C
How can i find best fit netmask for ...
-1
votes
3answers
200 views
Confusion about TTL when pinging
TTL value of a packet is supposed to decrease 1 at each router from 255 down to zero as follows:
But when I ping to 8.8.8.8 the TTL starts at 253 and doesn't change:
How can this be explained? Why ...
0
votes
0answers
16 views
Is 12.23.34.45/24 a valid IPv4 subnet definition? [duplicate]
I believe the question says it all: when referring to an IPv4 subnet, is it valid to use 12.23.34.45/24?
If it is, is it equivalent to 12.23.34.0/24?
If it is not, can you refer me to helpful ...
1
vote
2answers
22 views
Understanding IPV4 address range [duplicate]
I do have basic understanding of IP Address which is unique address for each System either in an organization or over the internet. But i want to understand what is IP address range
Lets Say we have ...
7
votes
5answers
2k views
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
13 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
votes
1answer
25 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
votes
1answer
28 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
votes
1answer
39 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
44 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
vote
2answers
29 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
votes
1answer
63 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
61 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
54 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
71 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
337 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
52 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
votes
1answer
36 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
votes
2answers
82 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
33 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
47 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
27 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
votes
2answers
46 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
93 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
209 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
33 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
378 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
62 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
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0answers
19 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 ...
