Questions tagged [ipv4]

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

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VLSM Network Devices

hi guys, so when my lecturer was explaining the process to do vlsm, they mentioned that for every cable linking to a device, you are suppose to add 2. eg(200,100,50,2*number of cable). but from what i ...
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2answers
2k views

How to choose IP address? [duplicate]

I have 2 sensors with the following IP addresses: Sensor A IP: 192.168.0.80 Sensor B IP: 192.168.1.201 I am able to connect them to my laptop separately using 192.168.0.100/255.255.255.0 for Sensor ...
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1answer
211 views

VLSM Determining Switch IP

i was given a network 130.4.0.0/16 that i needed to use vlsm on. which i did and got these vaules: Address | Mask| Assignable Range | Broadcast 130.4.0.0 | /22 | 130.4.0.1 - 130.4.3.254 | ...
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2answers
346 views

Does each router have the IP addresses of all the routers and hosts connected to the 'Internet'?

I am new to computer networking,and was reading about the topic routing. According to my understanding,each router has a routing table associated with it. From that table it could know,which output ...
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1answer
3k views

What is a Virtual IP (VIP)?

I heard a lot about virtual IPs (VIP) in WAF, VPS, NAT... but I still can't understand its concept. What is a Virtual IP (VIP) ? and how it differs practically from a Public IP ?
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1answer
130 views

Working Out A Router IP Address

in my exam i got completely derailed when i was asked to find the router ip address. i was given the following information about the network: VLANS: Managment Address: 198.72.210.64/26 Student ...
5
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1answer
153 views

Class A most significant bits '0' as in RFC1166 or older or '00' as suggested in RFC4632?

I was just reading RFC4632 "2. History and Problem Description" and I don't get the part about Class A with MSB '00'. That would in my understanding mean, there are actually only 64 available networks,...
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2answers
526 views

IP Address starting with 253

I have no idea if this is the right place to ask this question, I'm very sorry if it isn't I have here data containing an IP address that starts with 253.45.xxx.xxx But I've looked up everywhere and ...
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2answers
327 views

Why are Internet hosts “not required” to receive an IPv4 datagram larger than 576 bytes?

I'm currently studying Internet protocols and had a question regarding the IP datagram. Within the IP header I am aware there is a field called "total length" which specifies the total ...
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2answers
280 views

Does the same IP cause IP conflict if one is from /22 other is from /24?

I have two hosts. They both have the same IP/subnet, ex.: 1.2.3.4/24 on both. I know this is bad, since there will be duplicate IP in the network. OK. But: If I have different (?) ranges: 1.2.3.4/...
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1answer
140 views

What's the domain of an IP?

CIDR stands for "Classless Inter-Domain Routing". But what's a domain in this case? Seems to not be the same kind of domain as DNS deals with...
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Internet Protocol versioning - IPv4 and IPv6 [duplicate]

I know that IPv6 is the successor of IPv4. But I don't understand versioning policy. Why not IPv5? Did IPv1, IPv2, and IPv3 exist?
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1answer
233 views

Physical layer broadcast address and network layer broadcast address [duplicate]

For example here is an ip address: ip address:192.168.0.205 subnet mask:255.255.0.0 broadcast address:192.168.255.255 network address:192.168.0.0 My question is what does 192.168.255.255 do and ...
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1answer
3k views

Subnetting and switch configuration (CISCO Packet tracer)

I'd like to ask couple questions that I have about subnetting and switch configuration (more about latter). Currently, I have subnetted my network to be on IP 192.168.10.0/29 with subnet mask 255.255....
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1answer
730 views

Why would the local address in case of mobile data network not a private IP address? [closed]

I have connected my smartphone to internet over 4G through Airtel (ISP) I did - "What's my IP" on google. And below is the screenshot i obtained- I understand the public IP address is in the range ...
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1answer
101 views

Migrating from an IP addressing scheme to another one?

I have been tasked to migrate one of my customer's IP telephony network from 192.168.11.0/24 IP addressing scheme to 172.27.72.0/23. My customer has deployed Cisco Call Manager and Cisco Unity ...
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3answers
280 views

Use of /30 instead of /31

Besides wasting IP addresses. Is there any other compelling reason to use a /31 subnet over a /30 on Point to Point links? I am interested from a security perspective mainly. Would a /31 be more ...
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1answer
722 views

CIDR notation and subnets

I've been given a script that will create a virtual network with the following IP range (in Azure): 10.0.0.0/16. The script then goes on to create two subnets within that network with the following ...
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1answer
167 views

Were private IP ranges used publicly before inception of NAT?

I know NAT was developed to solve the problem of IPv4 address exhaustion. I am not very familiar with the history of how the Internet evolved (except ARPAnet because that is in every networking book). ...
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2answers
122 views

Subnet IP addresses from ISP multiple times?

I am new to networking. I was wondering if it is possible to subnet an IP from my ISP multiple times with different netmasks. For example, if I was given the IP block 141.13.0.0/16. Can I subnet this ...
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1answer
167 views

Analysing a HTTP request with tcpdump

I am trying to understand the acks from the sequence numbers in a TCP/IP packet. AFAIK, an ack from a transmitted package is calculated by the following [1]. In [2] I have an HTTP request to a site. ...
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1answer
92 views

OSPF - networks/links don't get advertised

In my Multiarea-OSPF configuration I can ping my neighbor, but nobody which is more than one hop away (for instance ABR2). Also traceroute just shows "1 * * * - 2 * * * - 3 * * *" Can ...
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1answer
6k views

Do routers discard packets if they don't know where to forward them?

If a router receives a packet whose IP destination address is not in its routing table, I believe it will send it to its default port. Suppose that we erase that entry from the table. Now, I think ...
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2answers
965 views

OSPFv3 - Sample configuration (Dual Stack IPv4 and IPv6) - Cheat Sheet

When configuring OSPFv2 on a router, you type in router ospf 10 router-id 1.1.1.1 network 10.0.0.0 0.0.0.3 area 0 for example. That way the network can be advertised per LSAs. But in OSPFv3 it ...
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1answer
5k views

Is a TCP server limited to 65535 clients?

One might think that this places a hard limit on the number of clients that a single computer/application can maintain. One could be overseeing a web server, and be required to ensure that it can ...
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1answer
100 views

Where do I need to assign the network address and the broadcast address

I'm about to take the second CCNA module exam and I have to configure routers and switches, but I can't understand something. So let's say i have this IP with this mask and i have to subnet, and you ...
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1answer
2k views

Does IP provide QoS or not?

IP provides a best-effort delivery service. I believe this implies, among other things, that it offers no QoS to the users. However, IP has a byte in its headers (ToS in v4 and Trafic Class in v6) ...
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2answers
2k views

Is there anything stopping me from using Class A addresses on my own network?

I've been reading about IPv4, networking, subnetting and the different classes of addresses. I understand that IP addresses beginning with numbers from 1 to 126 are considered "Class A" addresses. ...
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2answers
250 views

Two routers, one modem, dual IPs, second address drops connection occasionally

We have two ER-X connected via an unmanaged switch to a Cisco DPC3010 modem. Each is assigned a static WAN IP in a different block: 174.79.186.x/27 and 98.187.238.x/27. Every once in a while (roughly ...
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1answer
874 views

Understanding how IP Reassembly Process works

I'm trying to understand IP fragmentation and reassembly processes well. I found this example on the Internet that I guess would be useful to understand the topic. Suppose a certain computer recieves ...
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1answer
1k views

Can two networks have the same address with different masks? [duplicate]

Is it possible for two networks to have the same network IP address if two different masks are used? Take for instance the addresses 200.23.18.0/24 and 200.23.18.0/27. I'm thinking that this might be ...
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1answer
321 views

Is this IP configuration valid?

We have to install some network devices (ip camera, max=30) at one of our client sites, so we asked them to give us an IP range. The client sends the following details, IP range:= 192.168.0.264/296 ...
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4answers
2k views

Using IP subnet at multiple datacenters

We control IPv4 and IPv6 subnets. Now we'd like to use a part of a /24 IPv4 subnet at one datacenter and another part at another datacenter. I know that announcing the subnet on the internet at ...
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1answer
116 views

Can two networks be part of the same third octet subnet?

Can two networks be part of the same third octet subnet? If both networks are connected to their own respective links, then could their addresses all be a part of the third octet subnet? Say a ...
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2answers
874 views

Public IPv4 Subnetting Clarification

I've been delving into the wonderful word of networking (lol) and I have a few questions of clarification for IPv4 subnetting. I'm pretty comfortable with the idea of subnetting. I understand that it'...
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1answer
67 views

Can we use prefix address as the host address in ipv6?

IPv6 I read somewhere that we can use the first and last ip address as host addresses in ipv6. Is it true?
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5answers
2k views

Is a pfSense router w/ a LAN gateway using a /20 bits subnet mask common?

Obviously I'm lacking some networking knowledge, and I wish somebody could help me understand something fishy I found on a pfSense router in an organization yesterday. The pfSense router forces subnet ...
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2answers
3k views

Port numbers and private IP addresses in Port Address Translation

Sorry for my limited knowledge in Networking. If I understand correctly port numbers are application level addresses for network communication, e.g. port no 20 is assigned for FTP. In PAT, we map ...
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1answer
1k views

What does 10.0.0.0/32 mean?

I saw two IP addresses that I did not understand. 10.0.0.0/32 10.0.0.255/32 Are these broadcast addresses?
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1answer
143 views

Is there any current use of icmp features like Address Mask Request

I recently looked through the ICMP packettypes and there are some packettypes which in theory allow to request information from a host like the domain name, subnetmask, timestamp,... out of curiosity ...
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1answer
189 views

How do we interpret LSU in OSPF?

This is a kind of a very basic question in OSPF packet exchange. What are these kinds of link in LSU - Stub link, PTP and again Stub link. What I am trying to achieve here is to understand how a ...
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1answer
8k views

Identification field in Ipv4 header

Identification field is of 16 bits in Ipv4 header. This means we can have $2^16$ unique datagrams from a single host at a time. Also each datagram can have a total length of $2^16$ bytes. So can the ...
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2answers
257 views

Why subnetting is implemented if we can use Network Address Translation (NAT)

As in subnetting a block of IP adresses are allocated, which leads to consumption of those IP addresses. Then how come we don't use Network Address Translation (NAT) as it will only need one IP ...
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3answers
184 views

Subnetting and Private IPv4 Space

So, Looking online, the three private address blocks are: 192.168.0.0 /16 10.0.0.0 /8 And the weird 172.16-31.0.0 /12 So my question here is, why are we limited in this way? Is 192.0.0.0/8 in the ...
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1answer
682 views

UDP checksum calculation on improperly padded packets

Suppose I'm receiving IPv4 UDP packets whose payload is less than 18 octets, so when they are transmitted over Ethernet they have some trailing padding. Between the packets' source and my receiver ...
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1answer
47 views

What are “Unicast identity tokens”?

I was reading an introduction to IPv6 which talks about the depletion of IPv4 addresses. I came across the following line: As noted in RFC 5735 a number of address blocks are reserved for users ...
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1answer
81 views

Routing between network 1 and subnet of network 2 And their broadcast address

Suppose there's a network A with network 10.0.0.0 with network id=10.0.0.0 and Broadcast address 10.255.255.255 and Mask = 255.0.0.0 and network B with network 197.10.3.0 with network id =197.10.3.0 ...
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1answer
379 views

How does IPv4 know it has received a fragment?

So I'm reading about IPv4 and one of the questions are about how IPv4 knows that a fragment has arrived. Is it a certain header that is set?
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2answers
19 views

What kind of device do I need [closed]

I have two devices that need to be connected over wifi and get DHCP ip addresses both of them have ethenet ports so a figured I could save some money and get a external device that receives dhcp over ...
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2answers
3k views

Is there any difference between Limited Broadcasting and Directed Broadcasting when used in same network

I understand that limited broadcasting happens locally and can be done by using destination address as 255.255.255.255. The directed broadcasting happens across networks. To be precise, i want to ...

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