Questions tagged [subnet]

Questions relating to IP subnetting, including planning, calculation and best practices.

Filter by
Sorted by
Tagged with
0
votes
1answer
25 views

Can i/how discover subnet CIDR from IP range? [duplicate]

i have found the IP range 120.76.0.0 - 120.79.255.255 that i want to ban in iptables the way i write x.x.x.x/xx format. Please how to know what that x.x.x.x/xx should be? I have found some online tool ...
0
votes
0answers
8 views

How to select CIDR blocks when subdividing a network? [duplicate]

I saw these two questions, but they are still too over my head and start too far along the path: How to divide network into subnets? How do you calculate the prefix, network, subnet, and host numbers?...
0
votes
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
votes
1answer
47 views

Is it possible to know the mother address of a subnet?

The mother address is X, have Y numbers of subnets (children), we already know 2 of the mother's children, they're: 10.1.192.0 /20 [edited] 10.1.240.0 /20 Is it possible to know the value of X and Y ...
0
votes
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?
1
vote
0answers
13 views

Basic Subletting 10.239.142.216/11 [duplicate]

First time poster (kindly don't eat me alive) i was using https://subnetipv4.com/ to acid test my subletting skill i got 9/10 correct this is the chosen one that broke my streak as you can see i ...
-1
votes
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
votes
3answers
73 views

32 bits or 30 bits for subnet mask

I'm new to networking and have a question about subnet masks. Imagine we have a class B IP address. I know how to calculate the subnet mask. My question is: What is the last subnet mask that we can ...
0
votes
2answers
42 views

Network topology for merging two different layer 2 networks

I have a scenario, (shown in attach diagram) where i need to merge traffic from two server 1 , 2 to target server 3. All three are on different vlans/subnets. With layer 3 switch in between would it ...
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
votes
2answers
26 views

Can a Subnet have more than one CIDR range?

For many years I thought of a subnet as a single contiguous range of ip addresses expressed using CIDR notation. However on GCP a subnet can have a primary ip address range from which VMs get ...
0
votes
1answer
30 views

IPs that don't have subnet mask

I'm new to networking. I know that some IPs don't have a sub net mask like 127.0.0.1 and the range that starts with 127. I wanted to know if there is any other IPs that don't have sub net mask.
0
votes
2answers
36 views

Two routers on the same subnet - Possible issues?

What issues can occur when two routers are set to the same subnet (no cascading, both cable connected to the same switch)? For instance: - LAN: 192.168.1.0/24 - Router A: 192.168.1.254 - No DHCP, ...
1
vote
1answer
87 views

What is the last usable address in an IPv6 network

IPv6 does not have broadcast, so is the last address usable? Besides it being long, is it bad practice to actually use it? For example: A:B:C:D::0/64 starts with A:B:C:D:0000:0000:0000:0000 and ends ...
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
21 views

Additional subnets in a class C IP [duplicate]

If i'm designing a new subnet mask for a class C IP that will have 5 subnets that means I need to borrow 3 digits since 2^3-2 > 5. My question is, how many additional subnets do we have? would it be ...
0
votes
0answers
21 views

Subnetting for this question, please? [duplicate]

As a Network Support Engineer, you are tasked by your Supervisor with assigning IP addresses for your new MAN( Metropolitan Area Network) which consists of seven (7) different branches, each branch ...
1
vote
0answers
15 views

Split a Netmask into little chunks [duplicate]

I would like to know how I could divide a Netmask like 255.255.255.192 in 8 parts. Would it be something like this: 255.255.255.192 255.255.255.128 255.255.255.0 I'm really confused.
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 ...
0
votes
3answers
60 views

Multi LAN network does the main router to the internet need to be in its own subnet?

I have to design a network where there are 4 within which are different number of VLANs with varying number of hosts per VLAN depending on the building. My confusion lays in the main router, does it ...
0
votes
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 ...
1
vote
2answers
36 views

What is the suitable private IP? [duplicate]

What is the private IP that I may use if I am about to subnet a total of 743 hosts in my office? Should I use 10.x.x.x, 172.16.0.0 - 172.31.x.x, 192.168.x.x or all of them are allowed? Also if more ...
0
votes
0answers
8 views

Does 10.10.192.0/20 represent the same number of address with 10.10.195.0/20 [duplicate]

I knew 10.10.192.0/20 can represent the ip addresses from 10.10.192.0 to 10.10.207.255, but I'm confused how does 10.10.195.0/20 represent? I guess it is same with 192.0/20 right?
0
votes
0answers
15 views

CIDR notation confusion [duplicate]

So we are using CIDR for subnetting In that we just define the subnets by using / SO my question is if I am using /24 it means that I have the last octet for host. But if we use anything from /17 to /...
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
147 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....
1
vote
2answers
41 views

Why does the host machine need subnet mask? [duplicate]

The routers require subnet mask to route the packets to other routers or hosts, but why do host machines that are not routers such as computer running Ubuntu or windows need subnet mask to be ...
2
votes
1answer
79 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 ...
1
vote
2answers
59 views

Whats the proper way to write subnet size with / notation?

If I need to write a Subnet mask in /x notation, would it be correct to take the subnet id/X or the broadcast ip/x? I.e. for a 256 IP subnet: 10.10.0.0/24 or 10.10.0.255/24?
0
votes
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 ...
1
vote
1answer
90 views

Are subdomain and subnetting related concepts?

Recently while trying to grasp some basic networking concepts - I felt subdomain and subnetting are related concepts and wanted this group to confirm and add more insights on this. I understand that ...
0
votes
0answers
10 views

Can someone walk me through subnetting? [duplicate]

I'm trying to find the number of bits for subnet and the number of bits for hosts: The assigned network is: 10.0.0.0/8 The subnetted network is: 10.0.0.0/15 I have tried to do it, but I'm not sure ...
0
votes
2answers
66 views

VLAN based subnets, where should I untag a VLAN?

I have attempted to search this problem but I don't really know how to explain it properly (possibly a sign I've taken on more project than I can handle). Anyway I am currently working on chopping ...
4
votes
5answers
2k views

How does a host in one subnet know to forward the packet to the router MAC, when trying to send a packet to another subnet

I am trying to understand the ARP protocol and I could not understand the above. Consider the topology as follows: H1(1.1.1.1) - (1.1.1.0)R(2.2.2.0) - H2(2.2.2.2) My understanding is that if the ...
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 ...
0
votes
0answers
9 views

Given a subnet mask, how can I determine which addresses can be assigned to public network hosts? [duplicate]

For example, I'm given a subnet mask of 255.255.255.248 and need to determine from a list - 16.70.118.63 134.178.18.56 200.47.224.159 68.111.178.93 192.168.16.87 217.37.10.192 - which addresses can be ...
0
votes
1answer
80 views

Why is this subnet config required by my vlan “snake topology”?

I must validate the bandwidth on all 8 ports of a switch. We intend to do this with a "snake" topology as described in this article: http://thenetworksherpa.com/test-throughput-alchemy-using-a-snake-...
2
votes
2answers
299 views

Can a single subnet work across several switches?

New to networking and studying hard but limited access to a kit to try things at the moment... My question is - if I had, for example, two Layer-2 switches cable connected, could I have devices on ...
0
votes
0answers
13 views

Which mask to use for 1024 address size subnet [duplicate]

I am trying to identify if given IPs are from same 1024 SUBNET. 192.168.3.1 192.168.2.19 192.168.1.1 The part I got stuck is that SUBNET address size is 1024. If I am sure, by checking IP addresses ...
1
vote
1answer
98 views

Sonicwall: force all traffic from specific source through VPN

We have a main office (M) with a Sonicwall TZ215, and a branch office (B) with a TZ210. Computers in B access the server in M through a site-to-site VPN between the two Sonicwalls. Internet traffic ...
0
votes
0answers
21 views

Give the 36th subnet for given network [duplicate]

Given network is: 148.47.0.0/16, give the 36th subnet where you can uniquely address 54 hosts. Where to start? Thanks in advance.
0
votes
2answers
204 views

VLANs vs subnets pros and cons

What are the pros and cons of designing an entire network using VLANs rather than design the network only using subnets?
0
votes
0answers
11 views

How to divide an IPv4 network into three separate networks? [duplicate]

I have an address of 192.168.100.0(/24) and I need to separate it into three networks using VSLM. One needs 70 hosts, another needs 30 hosts and the last needs 25 hosts. What is the most efficient way ...
5
votes
3answers
769 views

CIDR and VLSM what are the differences?

CIDR improves the allocation of IP addresses. VLSM allows to define a subnet as we wish. Can CIDR used without using VLSM?
2
votes
1answer
56 views

How is traffic correctly routed in Site-to-Site VPNs where all sites are on the same subnet?

http://rockhoppervpn.sourceforge.net/ref_site2site_bridge_6.html The diagram on this page shows all 3 sites using the same subnet, 192.168.0.0/24. Let's say on the hub site where 192.168.0.10 is the ...
0
votes
0answers
18 views

How can a class b network with a cidr of 24 contain 254 networks? The third network IP octet is masked [duplicate]

class b network 172.16.31.0/24 with a mask of 255.255.255.0 contain 256 networks? the only range is 172.16.31.0 to 172.16.31.255 or are you saying that there can be 256 networks e.g Network 1 172.16....
1
vote
0answers
10 views

Can only same-sized networks be combined? [duplicate]

On multiple channels a "rule" is that only same sized networks can be combined. But this is only a valid constraint, if the subnet mask needs to remain the same as of the nets to be combined, correct? ...
0
votes
0answers
19 views

How to calculate subnet mask including, network address, gateway, broadcast address and host range? [duplicate]

You are defining network boundaries within a /24 network of 172.30.20.0/24. Please complete the segmentation of the /24 to account for multiple smaller networks of 115, 50, 28, 12, and 5 hosts. ...

1
2 3 4 5
11