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-1
votes
0answers
59 views

Subnetting assignment [closed]

My double lies in the underlined address block. In this case is it viable creating a subnetwork with R2,S2,V1,V2 in it OR just creating a R2,S2 one and V1 and V2 in separate ones by changing the ...
0
votes
3answers
105 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
65 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
278 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
186 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
721 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
301 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
64 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
157 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
226 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
142 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
6k 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
4answers
583 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
124 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
647 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?