Questions tagged [cidr]
The cidr tag has no usage guidance.
71
questions
3
votes
4
answers
12k
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AWS VPN Client connection to new VPC Endpoint is failing
I have set up a new VPN following the guide here. However when I try to connect to the VPN with the client i get an error "Connection failed. Try again." This happens every time. I opened the log file ...
0
votes
2
answers
5k
views
Issues with Ubuntu Network Setup
Please, someone tell me whats up here, I am going bonkers, I have used multiple calculators etc, everything tells me the details in the image are correct but ubuntu just will not accept.
5
votes
5
answers
1k
views
What does a CIDR mask mean in the context of "ip address add"?
I'm attempting to learn to set up Wireguard properly (not just by copy-pasting). I've come across this line on the quickstart page:
ip address add dev wg0 192.168.2.1/24
Reading the man page for ip, ...
4
votes
2
answers
8k
views
What is a correct IP4 CIDR for AWS?
I am trying to create some new subnets and cannot get AWS to accept a CIDR IP4.
I receive the message: Must be valid IPv4 CIDR. Nothing I try is accepted.
What is a valid IP4 for this purpose, and why?...
0
votes
1
answer
556
views
Adding more IP Addresses to a Subnet in AWS
I have a Subnet with CIDR 10.0.4.0/28 (15 IP addresses), which is now exhausted; so I want to add more IP addresses.
Is it possible to add more IP addresses to the subnet? I see that I can add a ...
0
votes
2
answers
121
views
AWS CIDR Address is not within CIDR Address from VPC
In AWS have created VPC which CIDR is 10.0.0.24.I want to creates its two subnet.its public-subnet is in us-west-1a - IPv4 CIDR 10.0.0.0/24 thenwhen I create private subnet is in us-west-1b - ...
1
vote
3
answers
5k
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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 the /...
0
votes
0
answers
447
views
How to update podCIDR for Kubernetes master node without recreating it
I have installed a Kuberntes system with one node,the node itself worked as both work node and master node,now I met a problem:
When the pod num exceed 255,Kubernetes will failed to deplopy it,after ...
26
votes
6
answers
38k
views
IPv4 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
3
answers
3k
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Check if IP Belongs to a CIDR
We have a list of CIDR's
1.10.10.0/24
5.154.0.0/16
5.181.219.0/24
23.90.68.0/24
31.40.214.0/24
I want to check if a IP for example : 23.90.68.56 belongs to any of the above CIDR's. If yes then we get ...
0
votes
1
answer
1k
views
AWS VPC Subnetting
I have a VPC created with a CIDR block of 10.10.0.0/16. I am trying to subnet that block into some /24's -- ie. 10.10.1.0/24
It wont let me. The error I get is:
CIDR Address overlaps with existing ...
1
vote
1
answer
6k
views
How do I route all public traffic through Wireguard but not local traffic?
I know there's a series of CIDRs that I can use to cover all public CIDRs and leave out local CIDRs, but I cannot find this anywhere and I don't recall where I found it a couple of years ago when ...
1
vote
2
answers
381
views
Resource handler returned message: "The CIDR '10.0.1.0/22' is invalid
I'm getting this error while trying to create a VPC with a Subnet in CloudFormation.
Subnet CREATE_FAILED Resource handler returned message: "The CIDR '10.0.1.0/22' is invalid. (Service: Ec2, ...
13
votes
2
answers
13k
views
Grepping for CIDR ranges
From time to time I want to grep CIDR ranges out of my Apache log files. This is easy for ranges that fall on the natural boundaries (/8, /16 and /24) but not so easy for other ranges such as /17 and ...
0
votes
1
answer
394
views
What does 0.0.0.0/0 mean?
For example in an 'allow' statement in BIND or in Chrony config files.
Does allow 0.0.0.0/0 mean allowing any clients or allowing no clients?
My question isn't about the specific programs, but just ...
0
votes
1
answer
310
views
"AWS CIDR is not within the CIDR ranges of VPC", but it is?
many questions on this, but this time doesn't seem as obvious as the others.
I'm trying to split a VPC in two subnets.
I start with VPC 10.0.0.0/24, 254+1 IPs, from 10.0.0.1 to 10.0.0.255
I create the ...
3
votes
2
answers
15k
views
Is it possible to change CIDR network flannel and Kubernetes
Is it possible to change CIDR network flannel on running Kubernetes cluster?
If yes what will happen with the launched pods?
Thanks
0
votes
1
answer
509
views
Can fail2ban-client tell me if an ip from a CIDR range is in a jail? [duplicate]
If I have a CIDR like 13.54.63.128/26 can fail2ban-client tell me if there's an IP in this range that's currently banned?
Currently I'm doing:
CIDR="13.54.63.128/26"
nmap -sL -n $CIDR | awk '...
0
votes
1
answer
316
views
Is it possible to communicate between different CIDRs?
For example, there are two CIDRs in the same VPC on AWS. One of them is public and one is private. They are in the different segment.
# Public Subnet CIDR
10.124.42.0/27
# Private Subnet CIDR
10.124....
2
votes
2
answers
2k
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Why does the Cisco RV180 not let me use a 255.255.254.0 subnet mask with a 192.168.2.1 LAN IP address?
I'm a Sysadmin for a tech company. We have a Cisco RV180 gateway device. We are at our breaking point for IP addresses, so we are changing from a /24 to a /23 subnet to allow for double the devices.
...
57
votes
6
answers
57k
views
What is the recommended CIDR when creating VPC on AWS?
I have been creating AWS VPCs and I am wondering if there is a recommended CIDR value when creating VPCs. What are the factors that I must consider when choosing a CIDR and does the CIDR value affect ...
-2
votes
2
answers
87
views
Identifying subnet bits of network addresses with same CIDR [closed]
Say we have network addresses 10.10.10.252/30 and 10.10.255.252/30 and 10.255.255.252/30. They all have CIDR of 30.
I realize all three subnets have two usable hosts.
All three addresses have subnet ...
-1
votes
1
answer
274
views
Banning an IP address
I banned an IP on my server, but I'd also like to ban using the CIDR method, e.g. IP/24.
My questions are:
How do I find the CIDR range of the IP address.
When banning the range, if the user has a ...
0
votes
0
answers
741
views
How to connect a VM to the Internet in VMware vCloud using a Network Gateway CIDR
I am familiar with managing servers and VMs that have their own IP address and network connection, but am now trying to host a VM in a VMware vCloud and am a newb for this.
I have created the VM and ...
0
votes
1
answer
218
views
Finding netid in CIDR [closed]
I am practicing questions related to CIDR and I have come across a particular question which I need some explanation. Can somebody please explain in detail how to answer this question.
An address ...
0
votes
0
answers
117
views
How to get range of ip addresses of current network
I am using AWS to host my website, recently I've been getting a lot of background noise on the server (bots trying to backdoor, etc.). I would like to limit access of my website to just our worksites ...
0
votes
1
answer
292
views
What is the VPC accepted address and why [duplicate]
i am trying to create a vpc but the ip i am providing is not accepted which is 192.168.1.1/16 but aws says i can use the following range if i set to 192.168.0.0/16 it works , i guess to an extent ...
-2
votes
1
answer
349
views
What if my public address is same as one of the IP address in my AWS VPC CIDR Block? [closed]
My public IP address (of my personal computer) from which I access the internet ranges from 112.110.x.x. For experiment, I created a VPC in AWS and chose the CIDR block as 112.110.0.0/16. In the route ...
0
votes
1
answer
835
views
Allowing external access to bastion hosts on aws
I am trying to create a few bastion hosts in my VPC on aws to connect to my databases that are located in a private subnet. I am using this aws Quick start.
I understand the basics of CIDR blocks ...
53
votes
6
answers
62k
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?
0
votes
2
answers
86
views
Subnet CIDR Scheme
I am redoing some VPC work that my predecessor did. I haven't setup a lot of networks, so I wanted to double check what I think makes sense isn't breaking some rule that I'm not familiar with.
What ...
3
votes
1
answer
988
views
Does 0.0.0.0/7 represent the same range as 1.0.0.0/8?
The range of 0.0.0.0/7 is 0.0.0.0 - 1.255.255.255.
The range of 1.0.0.0/8 is 1.0.0.0 - 1.255.255.255.
AFAIK, 0.0.0.0/8 (0.0.0.0 - 0.255.255.255) is not usable. So, do these represent the same range ...
0
votes
2
answers
43
views
AWS queries regarding subnetting and routing
I have some queries regarding AWS setup please clarify.
I have created a VPC with CIDR 172.16.0.0/16 which is a private range of IP's. In my route table, I routed all the traffic from this range. ...
3
votes
7
answers
2k
views
What does the netmask in an IP address actually tell you?
There are several questions out there asking what the CIDR netmask is, and how it's calculated. But after reading all the top answers, I'm still left wondering, how does the netmask let us distinguish ...
1
vote
3
answers
1k
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 ...
0
votes
1
answer
3k
views
What IP addresses are included in a subnet "range"?
I'd like some help understanding subnets (CIDR).
I'm using a tool to check if an IP is in an acceptable range given a CIDR address. When I input an IP address (12.245.105.190) and check it against ...
1
vote
0
answers
755
views
Adding exception to nginx HTTP basic authentication based on being on the local network
I'm running an installation of a webapp running on a self-hosted server which is on my main network along with all our company PCs and a couple of other servers.
We've decided we want to add HTTP ...
0
votes
1
answer
847
views
fail2ban - Filter IPs by cidr blocks
I'm using fail2ban 0.10.0 and with it I'm able to trigger some actions to block bruteforce attempts from a given single origin (with the HOST tag).
But suppose someone has control over an entire /24 ...
4
votes
1
answer
7k
views
Why is my AWS instance's private IP outside of the subnet's range?
I'm trying to launch an instance with the private IP address 172.31.32.101 using Terraform in my default VPC (CIDR 172.31.0.0/16), in the eu-west-1a subnet that has the CIDR 172.31.32.0/20. I can ...
7
votes
2
answers
4k
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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 10.2....
0
votes
1
answer
43
views
How will a router handle this destination address?
Let's say I have a router with three interfaces.
Interface #1 is 10.x.x.x /8
Interface #2 is 142.100.48.x /20
Interface #3 is 142.100.56.8 /21
I'm trying to send a file to [dest]142.100.57.5 from [...
1
vote
1
answer
126
views
How can destination addresses 132.148.77.28 and 132.148.77.28/32 be use different network interfaces for routing?
The output of netstat -rn on my FreeBSD virtual machine shows that:
Internet:
Destination Gateway Flags Netif Expire
default 10.195.51.254 UGS vtnet0
10....
0
votes
1
answer
2k
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Cannot get HTTPD 2.4 to start when using the Require IP command for access control
This was intended to be a comment on a similar question but since Stack is so restrictive about comments I'm reposting it as they want it:
: Here's the documentation: http://httpd.apache.org/docs/2.4/...
-9
votes
0
answers
2k
views
AWS Reserved IP addresses [closed]
I have multiple VPC in my account and I created most of VPC using subnet 10.0.0.0/8 or 192.168.0.0/16 or 172.16.0.0/12 subnet blocks.
I am exhausted with my range due to not optimizing the IP ...
26
votes
4
answers
22k
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 ...
0
votes
1
answer
561
views
Using a AWS VPN for client access to an internal web-application
I'm trying to connect a client's network to our AWS data-centre, to allow access to a (previously publicly available) internal web-application.
At the moment we've got the VPN set up with dynamic ...
0
votes
1
answer
2k
views
Connecting two AWS VPC Regions of the same CIDR range
Let say I have two VPC's (VPC-A with 10.50.0.0/16 and VPC-B with 10.50.0.0/16) in AWS with same conflicting/overlapping CIDR ranges in my AWS account. I already have the two VPC's fully functional ...
0
votes
0
answers
156
views
Can foreman handle nested subnets?
In Foreman 1.8 one can manage subnets through the web-interface at Infrastructure > Subnets. However, when I add a /24 (e.g. 10.10.0.0 with a subnetmask of 255.255.255.0), I cannot add anything less ...
0
votes
2
answers
16k
views
Google IP Address Ranges for incoming SMTP [duplicate]
Essentially I'm answering my own question here, but want to provide this info to anyone else who might need it. I need all the valid IP address ranges for Google Apps mail servers.
I'm configuring a ...
28
votes
6
answers
38k
views
Linux Command line tool to work with netmasks / CIDR notation [closed]
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?