Questions tagged [ipv4]
Refers to the 4th revision of the Internet Protocol, where addresses are usually displayed in the form of dotted decimals between 0-255. Ex: 169.254.0.1
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How does IPv4 Subnetting Work?
This is a Canonical Question about IPv4 Subnets.
Related:
How does IPv6 subnetting work and how does it differ from IPv4 subnetting?
How does Subnetting Work, and How do you do it by ...
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13
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Why couldn't MAC addresses be used instead of IPv4|6 for networking? [closed]
I am reading up on TCP/IP and other related protocols and technologies. MAC addresses are described as being (reasonably :) unique, and as having a large possibility space (several hundred trillions), ...
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How bad is IPv4 address exhaustion really?
For years the press has been writing about the problem that there are now very few IPv4 addresses available. But on the other hand, I'm using a server hosting company which gladly gives out public ...
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Do you need separate IPv4 and IPv6 listen directives in nginx?
I've seen various config examples for handling dual-stack IPv4 and IPv6 virtual hosts on nginx. Many suggest this pattern:
listen 80;
listen [::]:80 ipv6only=on;
As far as I can see, this achieves ...
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What is the rest of the 127.0.0.0/8 address space used for?
We all know what 127.0.0.1 is used for (loopback).
What are uses cases for the rest of the reserved 127.0.0.0/8 loopback space?
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What's the maximum number of IPs a DNS A record can have?
I have a strange idea - let multiple people/organizations host the same application, and let all their nodes be accessible via a single domain name. That's in order to have, let's say, a really ...
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Is it valid to have part of an IPv4 address set to zero?
I am working on a change in a Java EE application that would authenticate based on the user's IP address using ServletRequest.getRemoteAddr. We store IP address ranges (FROM_IP and TO_IP) in a ...
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Should my website have an IPv6 address?
My website only has an IPv4 address. With IPv6 being the future, is it possible that some users may not be able to reach the website if it does not have an IPv6 address? Also, does having an IPv4/IPv6 ...
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What makes a private IP address not routable?
I understand that private addresses such as 10.0.0.0/8,172.16.0.0/12 and 192.168.0.0/16 are not routable. However, what exactly is stopping these addresses from being routable? Do ISPs implement ACLs ...
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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 ...
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Is an IPv6-only MTA possible yet?
Has anyone had tried to run an IPv6-only SMTP engine?
Pretty much everybody with any sense has IPv6 configured for major front-end servers.
I was curious if anyone had tried to run an IPv6-only MTA ...
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New service decision: IPv6 or IPv4?
While hosting new service these days, what would be best decision. IPv4 or IPv6 ?
If we decided to launch it on IPv4 address:
How easy/difficult to get IPv4 address (considering they getting ...
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Difference between 0.0.0.0/0 and ::/0 in access control lists
When setting up access control lists, what's the difference between 0.0.0.0/0 and ::/0?
I'm seeing this for an AWS EC2 instance I'm setting up
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What is the name of an IP prefix with prefix length 31? (i.e. contains only 2 IP addresses)
At my job, IP prefixes with prefix length 31 (i.e. they only fit 2 IP addresses) are commonly described at "linknet addresses". Lately I have noticed that this term doesn't appear to exist ...
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How to completely, dynamically disable IPv4 stack from Linux?
How can I disable IPv4 stack from Linux ? I want to do that dynamically, i.e. sometimes I want it enabled and sometimes I want only IPv6 stack. Is there any portable way to do that ? If you know how ...
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Domain connection shows as "unauthenticated"
I have seen various different questions for this problem floating around but either the circumstances arent the same or the solution doesnt work so thought i would post it to see if anybody has any ...
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Why is ipv6 128bit and not 64bit?
Computer processors moved from 32bit to 64bit. Why have IPs moved from 32bit to 128bit (skipping 64bit) ?
EDIT:
I did not intend to make a direct comparison. Just curious why IPs skipped 64bit.
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Open Windows Firewall to all connections from specific IP Address
Is it possible to "whitelist" an IP Address in the Windows Firewall and allow all connections from that specific address?
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IPv6: How to start? (ISP perspective)
In our company we have a range of /21 (2048) IPv4 public addresses.
We have a bunch of Cisco routers and servers.
How to get started with IPv6? What can we do to provide internet to our clients with ...
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How do I make actual use an IPv4 block that I own?
We (a small French company) had reserved an IPv4 /24 block (256 addresses) from RIPE-NCC, over 20 years ago, but never used it. Update: our assignment belongs to the "Provider Independent (PI) address ...
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Disabling IPv4 and use only IPv6 in Ubuntu
I'm doing some IPv6 related testing, and I wanted to fully disable my IPv4 for the tests on Linux, but couldn't find any easy place to do this. How do I make my IPv6 the only active one?
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Are same IP address with different submask unique? [duplicate]
Possible Duplicate:
How does Subnetting Work?
In a same block of IPv4 addresses, can there be same IPs with different submasks?
For example, can I have this:
180.70.65.140/26
180.70.65.140/25
...
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How to prepare (or not) small company to IPv6
There's an ongoing "panic" all over the news for some time now about IPv4 running out and IPv6 being the savior. All the big companies are preparing and showing how it should be done (last actions ...
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1
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OpenVPN with mixed ipv4 and ipv6 clients
I have a VPN server handling various clients; some with ipv4 only, some with ipv4 and ipv6, and some that will be ipv6 only. Some of these clients are roaming, so ideally they should connect to ipv6 ...
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Prefer IPv4 incoming connections over IPv6
We run a social/local service that benefits from geolocating the IP of users. The problem is that with IPv6, geolocation is quite a bit spottier than with IPv4.
Is there a way to prefer incoming ...
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3
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How do I get anycast for my servers?
I want to have anycast for my web service, but I cannot find any information on how to achieve this or any company that can help.
I've found loads of companies offering anycast DNS, but that's not ...
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How does anycast work with tcp?
TCP, being stateful, should require subsequent packets to reach the same server. (Stateless) HTTP runs on top of TCP, and CDN's can use anycast.
So how does TCP work with anycast? What if the syn ...
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HTTPD listening in IPv6, according netstat, but reacheable in IPv4
Using Openstack, I have a Web GUI (horizon) hosted on my server (HTTPS).
When I do a netstat -lt | grep https, I have:
tcp6 0 0 [::]:https [::]:* LISTEN
...
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Why can't I ping an address on the loopback device under FreeBSD?
From Wikipedia:
The most commonly used IP address on the loopback device is 127.0.0.1
for IPv4, although any address in the range 127.0.0.0 to
127.255.255.255 is mapped to it.
This is not true,...
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IPv4 Properties Settings for servers on an isolated network?
I have a question related to servers which will not have any outside internet connection.
The topology is very simple :
I have an example IP address of 10.10.10.10 for the server and the workstations ...
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What determines whether the FQDN is interpreted as IPv6 or IPv4?
When I type a Fully Qualified Domain Name (FQDN) in my URL bar, the browser connects to some mapping table (where is this table stored? with the service provider?) that determines where the file ...
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Docker will only bind forwarded ports to IPv6 interfaces
Is there a way I can tell docker to only bind forwarded ports to IPv4 interfaces?
I have a machine running on Digital Ocean with IPv6 disabled:
# echo '1' > /proc/sys/net/ipv6/conf/lo/...
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Configure BIND to prefer IPv4 without disabling IPv6
Our office network is internally dual-stack, but the connection to the rest of the Internet is IPv4-only. I've got BIND 9.9 set up on a Linux box to handle DNS resolution.
Is there a way to ...
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Best choice of private addresses for a "device area network"
I'm building an appliance consisting of several subdevices connected by ethernet inside the appliance. The appliance will connect to the customer network. The customer network can be using private ...
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2
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American Users have wrong IP address geolocation
In order to display the right content for my users I get their country based on their IP address. I have been receiving several reports from American users saying that the content is being displayed ...
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Multicast hostname lookups on OSX
I have a problem with hostname lookups on my OSX computer. According to Apple's HK3473 document it says for v10.6:
Host names that contain only one label in addition to local, for example "My-...
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No IPv6 & DNSSEC support on cc-TLD? (practical implications)
I'm needing to register some domains that have country code domain extensions, but noticed that those TLDs do not officially support (A) IPv6 or (B) DNSSEC... What limitations or pitfalls should I ...
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Networking Question - What is a VALID Subnet Address? [duplicate]
Possible Duplicate:
How does IPv4 Subnetting Work?
I am currently revising Networking for the Cisco CCNA1. One of the questions that I am struggling to answer is the following:
Which of the ...
Phil
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2
answers
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IPv6 / IPv4 Third Form conversion?
I'm reading about how to configure IPv6 on Ubuntu, I've gotten to the section about Reading IPv6 Addresses and though the first two examples make sense to me, the last one escapes my grasp a bit, as ...
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How to disable ipv6 support in Linux entirely?
We are currently setting up a some local network servers to run in a full ipv4 network. I can be sure, that this network don't have ipv6 support, and never will.
Next to that,
partially because of a ...
user266008
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Can a global IPv6 address be NAT'd to an internal IPv4 address at a firewall-level?
As an organisation we've just requested our first IPv6 allocation. At present we are a wholly IPv4 organisation with a global IPv4 address allocation configured on our edge router and used (...
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Can the network still work when DNS & DHCP go offline?
In my LAN I have a Windows server and a Synology NAS for storage, directly attached to the server and provided as storage to the clients through a VM. The server provides the domain controller, the ...
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Disable IPv4: What exactly does 'ifconfig eth0 0' do?
I'm experimenting with Linux and networks. What I'm trying to do is disable IPv4 for remote connections. It shouldn't be that complicated but I didn't find much about this topic. However, there is one ...
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IP Address keeps getting assigned that is already in use
I have an internal IP Address (192.168.0.57) that every couple of days will get assigned to a machine which will then periodically lose it's connection to the network throughout the day.
The first ...
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Why 224.0.0.1 traffic is filtered by Linux hosts?
When sending an ICMPv4 echo request to a destination address like 224.0.0.1, it is ignored by Linux hosts receiving the request. The destination MAC address used is 01:00:5e:00:00:01.
The only way to ...
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IPv6: Should I have private addresses?
Right now, we have a rack of servers. Every server right now has at least 2 IP addresses, one for the public interface, another for the private. The servers that have SSL websites on them have more IP ...
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IPv6: the end of NAT? [duplicate]
Possible Duplicate:
Switch to IPv6 and get rid of NAT? Are you kidding?
Is NAT going to disappear with IPv6? What about during the "transition" from IPv4-IPv6?
How are we all going to access the ...
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Advantages of IPv4 over IPv6
In theory, how IPv4 is better than IPv6? I need only advantages of IPv4 for study purposes.
In another words - what are the pros of IPv4?
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Carrier Grade NAT concepts: IP bans
I'd like to deploy a Wireless WAN using IPV6 for at least the wireless bits given that 6 offers higher through-put. I'm exploring the concept of CGN and what strikes me immediately is the liability.
...
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2
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Empty AAAA DNS Record with long TTL?
I pay for a DNS service based on queries per second.
We are not using IPv6, but a large number of queries (that I pay for) are coming in for AAAA records. I understand that most DNS stacks will now ...
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