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 to upgrade to IPv6 for AWS EC2?

Starting yesterday, AWS is charging for IP addresses (IPv4). I would like to upgrade my EC2 instances to IPv6, but I must be missing the docs on how to do that? I can't seem to get an EC2 instance ...
Paul Draper's user avatar
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2 answers
464 views

How to force a server to return my IP address in IPv4 and not IPv6?

Scenario I have a tiny PHP script on a server that echoes the IP address of any client reaching it so the address can be added to the cpanel MySQL remote hosts table via the API. I call this script ...
user2834566's user avatar
-1 votes
2 answers
145 views

How to build a carrier-neutral data center?

We need to set up a very small datacenter. This needs to be carrier-neutral. What are the things we need to do to make it a carrier-neutral datacenter? I assume that we need internet connections from ...
Arafath M's user avatar
-2 votes
1 answer
115 views

Windows application listens on IPv4 but not IPv6 UDP

I have setup a Windows Server 2022 AWS EC2 instance. I installed and am testing an application that only runs on Windows. When setting up the EC2 instance I enabled both IPv4 and IPv6. AWS requires ...
Aaron's user avatar
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2 answers
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Server connection error on wifi

I have a server running debian 11 server running Mailcow. It works fine, but every now and then one of my clients will report a connection error. This connection error only appears when they use their ...
aforbes's user avatar
1 vote
2 answers
554 views

Devices keep getting IP from previous VLAN

Some devices (printers and laptops) that are moved to another building with a different VLAN will not release the IP address assigned. I noticed this first when a laptop reported no network ...
Rick's user avatar
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2 answers
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IIS 10 - IP Address And Domain Restrictions is denying all traffic

I have a server that has multiple sites set up on it in IIS 10. On one of the sites, I want to allow access to a range of IP Addresses, and deny traffic to the site from all other IP Addresses. In IIS,...
Bryan's user avatar
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2 votes
1 answer
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squid: Unable to allow 10.10.11.0/24 but 10.10.11.0/23 works

Im unable to make a working acl with CIDR over `/23` (squid 5.7 on Debian) For example i got this config (working): acl servers src 10.10.11.0/23 http_access allow servers ... http_access deny all ...
mylan's user avatar
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1 answer
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Access subnet from another subnet

I have ipv4 address 192.168.88.130 assigned by DHCP (cannot use static IP). I have to access devices on 192.168.20.X by changing adapter settings to static and assigning some IP from 192.168.20.X, and ...
gmijo47's user avatar
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Setting up Ubuntu vm and forgot to add a search domain

I was setting up an Ubuntu DNS server VM and accidentally forgot to add a search domain. How can I add this to my system? I set a static IP and had DHCP turned off on the machine. I am also using ...
frictionless's user avatar
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Use nftables to set up IPv6 NAT to IPv4

I am working on setting up a number of EC2 instances with IPv6-only networking. A few of these servers require occasional access to IPv4-only resources controlled by third-parties. Amazon has a blog ...
Moshe Katz's user avatar
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"Destination Port Unreachable" only on secondary IP of VM

An vmware VM is assigned two IPs. We can only ping one of the two IPs from VMs on the same network. 2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen ...
Vladimir's user avatar
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347 views

Dual Stack Kubernetes cluster assigning single stack IPs to pods & services

I am creating a dual stack Kubernetes cluster with kubeadm, and installing Calico. I am using the below configuration file for kubeadm: apiVersion: kubeadm.k8s.io/v1beta3 kind: InitConfiguration ...
Eddie Aspden's user avatar
-1 votes
1 answer
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Internet reachable from the first subnet, not from the second, on same NIC

Hi (I hope this a the right place) I'm working on ubuntu 18.04 with ifupdown (/etc/network/interfaces etc.), not netplan. I'm trying for several days on this difficulty. one PC (A) with 2 cards : ...
romaillard's user avatar
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543 views

iptables rules - Forward/Masquerade sevices using nat table

I need to complete an exercise with iptables on a network (docker containers) configured as follows: A router host with 2 network interfaces (eth0 <- public 10.9.0.0/24; eth1 <- lan 192.168.60....
Giuseppe's user avatar
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IIS 10 - how to block an IP range

I'm trying to figure out how to block by range on MS IIS 10, but all I can find are partial range blocks (which maybe that's all IIS can do, but I'd like to know that rather than just guess that). So, ...
Merennulli's user avatar
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1 answer
181 views

Tuning Amazon Linux for TCP Handshake, receiving 200-300KB response, and then closing connection

I have an application which regularly creates a new TCP connection, makes a request, and then gets a just under ~300KB response before closing down the connection. Assuming that I can't redesign this ...
Cory Kendall's user avatar
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1 answer
38 views

Set IP address from VPN service (not from internet service provider) as main IP for server

I’m currently trying to get 3-4 servers for our business, situed in our office, but the main problem for us is IPv4, as in Canada, ISP charge basically ~15$/month for a single IP. It not really a ...
Wtrnd's user avatar
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1 vote
0 answers
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Linux confusing MAC addresses for its IP addresses to Cisco switch?

I have multiple CentOS boxes (both Centos 7) with two different servers. These servers have 4 10GB interfaces each. They are connected to two Cisco Nexus switches. Each NIC has a different IP address, ...
user1955162's user avatar
1 vote
3 answers
3k views

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 ...
ph3ro's user avatar
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1 answer
2k views

Can't add second IP adress via Netplan on Ubuntu

So I have a dedicated server for which I need a second IP adress. After ordering the adress the hoster just told me that i can now use the ip (giving me the IP, gateway and netmask). OS: Ubuntu 20.04....
flololan's user avatar
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-4 votes
2 answers
1k views

Why are Class E IPs in use?

According to all documentation, class E IPs - those in the range 240.0.0.0 to 255.255.255.255 - are for research purposes only and should never be assigned or used. And yet, according to a review of ...
sgfit's user avatar
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Windows Server 2016 unpredictable static routes

I am configuring routes on a Windows Server 2016 machine. I've already set up a Lan to Lan VPN as follows on a DrayTek router: Local network: 10.23.42.96/29 Remote networks: 10.41.73.0/24, 10.41.86....
Hackjaku's user avatar
1 vote
1 answer
254 views

While using pf on FreeBSD, do I need to explicitly specify both the inet and inet6 parameters?

Suppose I have a rule like rdr on $ext_if inet proto tcp to port https -> $inf_if port $myhttps This is to redirect incoming TCP packets on the https port to a specific internal IP/port. This is ...
ahron's user avatar
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0 answers
156 views

How can i access ipv4 on ipv6 server having nat ip4 with blocked ipv4 access?

I have a nat vps, there are some restrictions set by hosting company because of many abuses, they provide nat ipv4 and dedicated ipv6 on a server, before the server was working normal like i can ping ...
Blohsh's user avatar
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0 answers
405 views

How to prevent NetScan on a dedicated server?

we have a dedicated server from Hetzner, we are using it to provie nat vps to users, the problem we are facing is that users (which we don't know how to trace) is attempting netscan due to which our ...
Blohsh's user avatar
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4 votes
1 answer
4k views

Purpose of IPv4 mapped IPv6 address

I am still confused about the purpose of IPv4 mapped IPv6 addresses and would like some enlightenment. I have a server client pair of machines and I intend to connect them via Openvpn. The server has ...
Mervyn Heng's user avatar
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2 answers
365 views

Channeling IPv4 packets to IPv6 packets between interfaces

How do I route packets in my machine between interfaces (See yellow arrow). Eth0 receives IPv4 packets and I will like to channel it to Eth1 which will send IPv6 packets out.Image of dual stack ...
Mervyn Heng's user avatar
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0 answers
533 views

Split /24 IPv4 subnet into multiple /28

I would like to know if it is possible that a subnet /24 that I assigned to a dedicated server (via BGP session) can be divided into smaller subnets without the intervention of those who have access ...
F.Hazi's user avatar
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-2 votes
1 answer
45 views

Specify different broadcast IPs for different Windows machines [closed]

I run some high-frequency trading software from home across multiple accounts. Sometimes during very volatile conditions, I run into issues with rate limits restricted by IP address. I was assuming I ...
Will Calderwood's user avatar
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0 answers
154 views

Centos7 server that has no IPV6 assigned to it, can't read IPV6 ips in access log

I'm using CentOS7, nginx as a reverse proxy and apache web server. This server doesn't have IPv6 assigned to it, therefore there is no IPV6 in the NIC. This server hosts several websites. When I check ...
Stas Styler's user avatar
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0 answers
269 views

IPv4 fragmentation and high speed data

Please excuse me if this has been answered before, but I couldn't easily find an answer. My company creates high-speed measurement equipment, that produces roughly 0.7 Gigabit/second of UDP data. Each ...
Roel Baardman's user avatar
0 votes
2 answers
2k views

Service bound to ipv6 on linux machine - Can I disable IPV6 and access service on my IPV4 address?

I am attempting to install Tableau Server on Ubuntu 18.04 and have the management service running on port 8850. I am unable to access the service at that port on my IPV4 address as it seems to be on ...
Kelvin Lawson's user avatar
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1 answer
554 views

What does exactly break with double NAT?

There are many warnings about double NAT networks. DSL---modem with router-----second router configured by ISP inner network first NAT second NAT What will exactly break ...
Jonas Stein's user avatar
0 votes
1 answer
13k views

What is the IPv6 equivalent of 127.0.0.1 [duplicate]

The IPv4 address 127.0.0.1 is for the local/current client. What is the opposite of the address in IPv6? I already searched for it, but only found ::1. Is this the correct one?
Niklas's user avatar
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0 answers
2k views

Force DHCP client to use only IPv4

I have Linux client (running systemd-networkd, version 244), and I want to configure it's network only with IPv4. However, the DHCP server offers both v4 and v6. Is it possible to limit the client to ...
user951769's user avatar
3 votes
2 answers
2k views

Why will Firefox resolve my domain but Chrome will not

I've been setting up a LAN DNS server using DNSMasq to forward my webserver which at the moment has https and is port-forwarded by my router. I have a domain registered which resolves fine from ...
Adam  M.'s user avatar
  • 161
9 votes
3 answers
2k views

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 ...
MFerguson's user avatar
  • 193
-2 votes
1 answer
47 views

Packets sent in IPv4

I'm just trying to understnd how packets work. So if i hypothetically had a image of a size of 1mb which is 1,000,000 bytes and the maximum packet size for a IPv4 packet is 65,536 bytes does that mean ...
Ferroxel's user avatar
4 votes
1 answer
12k views

How to fix, ubuntu not getting ip address on hyper-v?

I am using hyper-v as a hypervisor and installed ubuntu 21 on it. There, whenever I start the VM, the eth0 (only one network interface connected,Default Switch of Hyper-v) is not getting IP and ...
Sara June's user avatar
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0 votes
1 answer
151 views

IPv6 vs IPv4 available subnets - enough or too less

I read a bit about IPv6 and found that usually you get assigned a /48 prefix address. Which gives you 16 bit for subnetting. Reading further assuming that you use /64 subnets you would end up with ...
metriXc's user avatar
6 votes
1 answer
2k views

Which ICMP types (v4/v6) should not be blocked?

I have made a lot of research into this and have found that some references contradict each other. IPV6 For example RFC4890 says the following types should be allowed for optimal functionality: Type ...
Houman's user avatar
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0 votes
1 answer
249 views

How to proxy ftp connection between IPV4 server to an IPV6 client and vice versa

We have a gateway solution which connects legacy RADIO's having ftp server running with IPV4 interface to DU's running with IPV4 ftp clients to do file upload and download operations. And currently we ...
Neeraj's user avatar
  • 1
1 vote
2 answers
1k views

Whitelist both IPv4 and IPv6 in AWS Security Group

I am setting up an SFTP server, I want to white list all the IPs in the Security Group so people can connect to it from anywhere. At the moment I am adding 2 rules to the Inbound rules, one rule for ...
Hooman Bahreini's user avatar
0 votes
0 answers
2k views

Cannot ping two computers with each other on the same switch. (Newbie)

I am an absolute 0 in network science and I would like to understand it a little bit. We have an offline machine connected to a switch, which is also connected to a series of other hardware that ...
lexax127's user avatar
-1 votes
1 answer
1k views

How can I disable IP forwarding from IPv6 toIPv4

I have IPv4 and ipv6 addresses on my network card, when I send a request with curl I want only the respective IPv4 or IPv6 to be used and no fallback e.g. When IPv6 to IPv4 takes place. curl --...
Myra Sewitz's user avatar
0 votes
2 answers
254 views

Why does facebook only have 2 IP addresses? [closed]

In the process of setting up DNS for my own website I got curious about looking up a large company's DNS record. I chose facebook.com and used dnschecker.org to view their dns record. Ignoring AAAA ...
Currn Hyde's user avatar
0 votes
2 answers
2k views

About 198.18.0.0/15 segment

What exactly is the use case of 198.18.0.0/15 segment As per whois records, this segment is reserved as depicting below - NetRange: 198.18.0.0 - 198.19.255.255 CIDR: 198.18.0.0/15 NetName: ...
Gaurav Kansal's user avatar
1 vote
0 answers
200 views

Are their public IP ranges which don't belong to any country?

I've been working on project and we use IP geo-location using an API to identify user's country. The legacy code has an edge case when there is no country information for a particular IP. I have been ...
CodePanda's user avatar
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0 votes
0 answers
154 views

How to blacklist the "prefix" of IPv6

With IPv4 it is pretty easy to blacklist IPs since it's not cheap to get new IPs and they are limited. However, with IPv6 it's pretty easy/free to generate a huge amount of unique IPs and it's pretty ...
Dani's user avatar
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