39 votes
Accepted

I have both IPv4 and IPv6 public addresses. Why?

Firstly, what is the purpose of me being assigned one of each type? Ideally, we should be moving towards greater IPv6 rollout, due to IPv4 exhaustion. However, a lot of servers still don't support ...
Bob's user avatar
  • 61.7k
39 votes
Accepted

Are IPv4 ports separated from IPv6 ports?

Yes, definitely. In fact, there is even a difference between a port on TCP vs that same port on UDP on the same IPv6 address, which is why you specify -p tcp as well. IPv4 is a different mechanism ...
LPChip's user avatar
  • 61.6k
37 votes

Why is there a percent sign '%' in the IPv6 address?

The characters after the % (which happen to be numbers in your example) are the "zone ID". (The "zone ID" is text that identifies which helps identify which network card to use. ...
TOOGAM's user avatar
  • 15.8k
21 votes

Disable IPv6 with OpenWRT

A simpler approach would be to SSH into your OpenWrt router and execute the following commands: uci set 'network.lan.ipv6=off' uci set 'network.wan.ipv6=off' uci set 'dhcp.lan.dhcpv6=disabled' /etc/...
Sir Muffington's user avatar
18 votes

what's IPv6 analogue for IPv4 `arp -an` and "arp who-has"?

ip -6 neigh show Above command is to check arp table for ipv6
Vijay S B's user avatar
  • 293
16 votes

Disable IPv6 with OpenWRT

On initial installation (or settings reset) OpenWrt generates a Unique Local Address prefix and assigns ULAs to all the devices in the network, allowing them to communicate internally via IPv6 even ...
Michael Hampton's user avatar
15 votes
Accepted

How web browser determines when to use IPv4 or IPv6 to connect to the destination?

First: How you resolve a hostname has nothing to do with what address you can resolve it to. DNS servers are perfectly capable of returning IPv6 AAAA records when asked via IPv4, and vice versa. As ...
u1686_grawity's user avatar
14 votes

How to disable autoconfiguration on IPv6 in Linux?

The sysctl solution did not work for us on Ubuntu 18.04 Bionic. We solved it by: Editing /etc/netplan/01-netcfg.yaml, configure: network: ... ethernets: eth0: ... dhcp6: no ...
Jeroen Vermeulen's user avatar
14 votes
Accepted

Is the Windows Firewall mode "Private" obsolete with IPv6 for home users?

No. Neither the Windows firewall nor a competent router's firewall is "all or nothing". Home users are generally expected to set the Windows Firewall to the Private profile when they are connected ...
u1686_grawity's user avatar
13 votes
Accepted

Debian/Mint/Raspbian/Ubuntu - How to force SLAAC EUI64 IPv6 autoconfiguration?

You are confusing two different address types: temporary addresses generated according to RFC 4941 "Privacy extensions", permanent addresses generated according to RFC 7217 "Opaque interface ...
u1686_grawity's user avatar
12 votes

How to get the IPv6 IP address in Linux

/sbin/ip -6 addr | grep inet6 | awk -F '[ \t]+|/' '{print $3}' | grep -v ^::1 | grep -v ^fe80 The output of /sbin/ip -6 addr | grep inet6 looks something like this: inet6 ::1/128 scope host inet6 ...
Qian Chen's user avatar
  • 213
12 votes

Are IPv4 ports separated from IPv6 ports?

Yes, they’re entirely separate. In POSIX, you create sockets using the socket(2) system call, and you pass AF_INET or AF_INET6 to it to choose between IPv4 and IPv6, respectively. Such sockets can use ...
Roman Odaisky's user avatar
11 votes

How to get the IPv6 IP address in Linux

To get only the IPv6 addresses you use the ip addr command and filter already with -6 for IPv6 addresses only. ip -6 addr If you want to specify a network adapter you might append show dev eth0 while ...
LUXS's user avatar
  • 211
10 votes

Ubuntu IPv6 ping self gives unknown host

Works with /64 removed and -I specified. The /64 refers to the number of bits in the mask and shouldn't be used in ping. $ ping6 -c 1 -I enp0s25 fe80::ba94:3d5e:9929:4c6e PING fe80::ba94:3d5e:9929:...
jws's user avatar
  • 260
10 votes
Accepted

Match IPv6 protocol using nftables

TL;DR: Be sure to use an inet family table and not the default ip family, as described in the wiki: Both IPv4/IPv6 packets will traverse the same rules. Rules for IPv4 packets won't affect IPv6 ...
A.B's user avatar
  • 5,936
9 votes

How to disable ipv6 on a specific interface in Linux?

One way to temporally remove the ipv6 on an interface is: (it will come back after reboot) ip -6 addr flush eth0
lepe's user avatar
  • 738
9 votes

How to connect to a website that has only IPv6 addresses without a domain name?

If required to test locally with IPv6, put the below AAAA Record in the address bar: [::1] This is equivalent to writing: localhost or to this IPv4 A (Host) Record: 127.0.0.1
AKS's user avatar
  • 191
9 votes
Accepted

Chrome not using hosts file for IPv6 addresses since v73

There is a know bug in Chrome which might be responsible for your problem: Issue 530482: Can't reach private IPv6 hosts on networks without global IPv6 connectivity. The discussion in the bug report ...
harrymc's user avatar
  • 482k
9 votes

Are IPv4 ports separated from IPv6 ports?

In short Yes Note that application doesn't have to bind to both IPv4 and IPv6 so you could do this even without IP tables. Look at the ListenAddress directive in your sshd config or other application. ...
Rodney's user avatar
  • 201
8 votes

Why is ARP replaced by NDP in IPv6?

The introduction of NDP in lieu of ARP was mostly due to the desire to consolidate the control protocols around IP. IPv4 enjoys several control protocols such as ICMP, IGMP, and ARP/RARP. With IPv6 ...
countermode's user avatar
8 votes
Accepted

How to specify IPv6 link-local bind address in smb.conf?

After hours of struggling, try, error and reading source code. Everything works well but you have to specify correctly. When using IPv6 LinkLocal addresses you have to specify the interface with the "...
Martha Gottsumpf's user avatar
8 votes
Accepted

Identify device on local network based on IPv6 address

Thanks to this comment on another Super User answer, I discovered the command: netsh int ipv6 show neighbors To my great joy I discovered it tells me the MAC address of devices on the local link, ...
I say Reinstate Monica's user avatar
8 votes

Ubuntu IPv6 ping self gives unknown host

You should not use the /64 on the address in the ping. That would be the equivalent of using a mask length or mask on the ping command for IPv4. I suppose the ping command was trying to interpret that ...
Ron Maupin's user avatar
  • 3,425
7 votes
Accepted

What's better RADVD or DHCPv6 for local network with IPv6?

You need at least radvd. Router advertisements communicate to devices on the network what the default gateway is and what the network configuration is. You always need that. The router advertisement ...
Sander Steffann's user avatar
7 votes

Disable or enable IPV6 in router?

There is some ambiguity about enabling and disabling IPv6. Even 6 years ago where things were much worse for IPv6, Cisco claims that it shouldn't be disabled. Some people connecting to dual-...
Jimmy_A's user avatar
  • 1,199
7 votes
Accepted

How does someone obtain a large block of IPv6 adresses?

That's a tiny block. IPv6 addresses aren't counted individually, except by cheapskate VPS hosting companies. More often, a /64 subnet containing 2^(128-64) addresses – 18 billion billion ...
u1686_grawity's user avatar
7 votes
Accepted

Why is IPv6 still dynamic?

Devices on the Internet are assigned a unique IPv6 address, which causes concerns for privacy and tracking. To mitigate the problem, the IPv6 address assigned to a device by the local router is ...
harrymc's user avatar
  • 482k
7 votes
Accepted

Why does peer-discovery work for IPv6 but not IPv4?

And the peer-discovery functionality that I've built works by simply sharing the IP address of connected nodes along with their announced port for incoming connections. There are a few issues with ...
u1686_grawity's user avatar
6 votes

IPv4 vs IPv6 priority in Windows 7

Short version Before September 2012 After September 2012 Precedence Prefix Precedence Prefix ---------- ------------- ---------- --...
Ian Boyd's user avatar
  • 22.2k
6 votes
Accepted

how to configure radvd for linux ipv6 router towards upstream dsl gateway

The issue I have is that the DSL router is sending neighbor solicitations packets on eth1 when it gets inbound packets from the internet, and those neighbor solicitations are not being passed from ...
u1686_grawity's user avatar

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