The cidr tag has no wiki summary.
3
votes
1answer
127 views
Subnetting into 6 CIDR/24 network and 2 CIDR/27 networks?
I am revising some questions for an exam and one of the questions was provide the ip numbers and a diagram for a company which has 3 branches. Paris/Berlin/Cairo (random locations I know) Now I belive ...
0
votes
0answers
104 views
Multiple IP Blocks in pfSense
How can I implement CARP shared IP and WAN access for multiple public IP blocks in a CARP-enabled pfSense cluster? For example, say I have 11.11.11.129/27 and 11.11.12.129/27, which of the following ...
6
votes
1answer
134 views
If I change a router's subnet mask to one that includes the old one, will the hosts with the old configuration still work?
Currently I have a router that is addressed as 10.2.1.1 on a 10.2.1.0/24 network. All of my hosts have default gateway 10.2.1.1 with mask 255.255.255.0.
I want to know: if I change my router to ...
0
votes
3answers
193 views
A Way To Determine IP Range From CIDR? [closed]
Possible Duplicate:
How does Subnetting Work?
Is there a formula or a calculator for determining an IP address from CIDR that I was given: 38.103.17.160/27?
I would like to know the ...
1
vote
1answer
100 views
Openvpn: iroute for all theoretically reachable [public] IPs
I am testing the creation of an enforced default route of only public IPv4 space via OpenVPN. OpenVPN does not support 'iroute 0.0.0.0 0.0.0.0' out of the box, because it contains code that rejects ...
7
votes
4answers
319 views
CIDR Ranges for Everything except RFC1918
I'm looking for a list of CIDR blocks for "The Internet", i.e. everything from 0.0.0.0 to 223.255.255.255, excluding RFC1918 address space of 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 (yes, I know ...
1
vote
2answers
212 views
Can I divide a /28 network into two /29 networks?
I have a
192.168.1.64 /28 Network
Can I divde this network into
192.168.1.64/29
and
192.168.1.72/29
?
My Question is related to the fact that now the "network address" (192.168.1.64) of ...
0
votes
4answers
921 views
Can't authorize a server for Amazon RDS
We are attempting to slowly migrate a website over to AWS among other things. We decided the first thing to move was the database. We have some dedicated server with a different hosting provider. We ...
4
votes
2answers
342 views
Reverse DNS Delegation from ISP
I get a /29 Delegated to me from Verizon(Fios) and I got them to delegate rDNS to my Name servers, I Notice that with some systems that it works and is able to get my PTR record, but on some it isn't ...
0
votes
1answer
67 views
subnetting a class c on a cisco 3825
I have a class C that I want to better understand before I implement a change.
Right now,
ip address 192.168.0.1 255.255.255.192
ip address 192.168.0.65 255.255.255.240 secondary
So, where is ...
1
vote
6answers
162 views
Trouble subnetting a network
I have the network address 160.80.0.0/24 and have to subnet things like this:
How would I subnet this network to accomodate such a huge number of hosts? :D Any guidance for a newbie? I've already ...
0
votes
6answers
239 views
Is there a tool for subnetting for free?
I'd like a program that I can write in an IP address and give it the Subnet mask and have it divide the networks in C level networks.
Thanks.
Something that I can download please, not a website.
1
vote
2answers
155 views
How to determine largest cidr in a range of IPs
Say I've got a begin ip and an end ip. What would be the easiest way to figure out the largest cidr I could allocate from this range in order to reduce fragmentation?
For example, I have the range ...
4
votes
1answer
7k views
What does 192.168/16 mean? [closed]
OK, this isn't really a server question in practice, but I'm pretty sure it has something to do with server management.
What is this joke supposed to mean?: http://xkcd.com/742
3
votes
3answers
850 views
13 IP addresses, how to add them to domain SPF?
Let say I have these IP addresses on my server:
170.120.210.209 gateway
170.120.210.210 server IP
170.120.210.211
170.120.210.212
170.120.210.213
170.120.210.214
170.120.210.215
170.120.210.216
...
3
votes
1answer
126 views
Is it safe to assume that two hosts on the same /24 network belong to the same AS-number?
Assume two IP-addresses in the same /24 network (say 1.2.3.*):
1.2.3.X
1.2.3.Y
Is it safe to assume that these two hosts belong to the same AS-number? If not, roughly how often is that the case ...
4
votes
4answers
709 views
Linux Command line tool to work with netmasks / CIDR notation
I'm terrible at working out network subnets in my head. Is there some command line tool for linux (ubuntu packages a plus), that lets me put in 255.255.255.224 and it'll tell me that is a /27?
2
votes
1answer
2k views
How To Add Multiple /24 Network IPs in Ubuntu
We have a client who needs to set up 2 Class C (/24) address ranges in Ubuntu. We have a single nic connected to the switch currently and the IPs are set up at the switch.
We have done this many ...
11
votes
4answers
4k views
Reverse DNS in a CIDR world
Reverse DNS seems to be strongly tied to class boundaries, what methods exist now that CIDR is the standard to delegate authority for a subnet? If multiple methods exist which one is best? Do you ...
13
votes
6answers
3k views
CIDR for Dummies
I understand what CIDR is, and what it is used for, but I still can't figure out how to calculate it in my head. Can someone give a "for dummies" type explanation with examples?
