Internet Protocol version 6 (IPv6) is the latest version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.

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79
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9answers
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Convince apt-get *not* to use IPv6 method

The ISP I work at is setting up an internal IPv6 network in preparation for eventually connecting to the IPv6 internet. As a result, several of the servers in this network now try to connect to ...
17
votes
1answer
3k views

sysctl: /proc/sys/net/ipv[46]/conf/: what's the difference between “all”, “default” and “eth*”?

In sysctl, the /proc/sys/net/ipv[46]/conf/ keys have the following subkeys: all, default, and a key for each network interface. For example, on a machine with a single network interface eth0, it will ...
8
votes
2answers
17k views

“IPv6 support is disabled” warnings

I get the error while running a script which tries to send emails. send-mail: warning: inet_protocols: IPv6 support is disabled: Address family not supported by protocol send-mail: warning: ...
8
votes
1answer
161 views

Blocking SSH Brute Force attacks on IPv6

I recently had to work with some servers that have an IPv6 connection and I was surprised to find out that fail2ban does not have IPv6 support, neither does denyhosts. Searching on google I found that ...
7
votes
3answers
422 views

How to use shell to derive an IPv6 address from a MAC address?

We know that we can use the MAC address to create an interface identifier, e.g. for a link-local IPv6 address which should be unique in the Network. The image shows the way to do this: My ...
6
votes
2answers
3k views

What is the purpose of avahi on a RHEL 7 server?

Running a server machine with CentOS 7, I've noticed that the avahi service is running by default. I am kind of wondering what the purpose of it is. One thing it seems to do (in my environment) is ...
6
votes
2answers
52k views

Static IPv4 & IPv6 configuration on CentOS 6.2

I try to configure static IPv4 & IPv6 configuration on CentOS 6.2. The configuration below works perfectly : # ifconfig eth0 x.x.x.x/29 # route add defalt gw x.x.x.y # ip addr add dev eth0 ...
6
votes
3answers
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Is it better to set rules in ip6tables or disable ipv6?

I have the following network configuration: # ifconfig -a eth0 Link encap:Ethernet HWaddr 00:e0:1c:73:02:09 inet addr:10.1.4.41 Bcast:10.1.255.255 Mask:255.255.0.0 inet6 ...
6
votes
1answer
3k views

avoid IPv6 link local address on interface

I have a setup with virtual Xen hosts connected to a set of VLAN-s. On Dom0, I have set up a bridge for each of my VLAN-s to connect DomU-s to. Bridges are set up in /etc/network/interfaces like ...
6
votes
3answers
4k views

How can I disable automatic IPv6 neighbor route advertisement on a router?

I work for an ISP that's in the process of making its infrastructure IPv6-ready. Our core routers already have a working setup, but a large portion of our fiber customers are behind a router running ...
6
votes
2answers
2k views

How to disable requesting AAAA records when I have no IPv6 address?

Why can I see AAAA DNS requests when I run tcpdump on my Scientific Linux PC when I haven't got any IPv6 addresses? I already rebooted after setting NETWORKING_IPV6=no in /etc/sysconfig/network and ...
5
votes
2answers
924 views

Route and “e” flag

k# route -6 Destination Next Hop Flag Met Ref Use If ::/0 fe80::8001 UGDAe 1024 0 0 eth0 [...] What does flag "e" mean?
5
votes
1answer
3k views

Routing public ipv6 traffic through openvpn tunnel

What I'm trying to do is to route IPv6 traffic through a vpn tunnel. That way, I should be able to use IPv6 in a network that doesn't support IPv6. I have a VPS which has an IPv6 block assigned. Part ...
4
votes
2answers
205 views

IPv6 Zone ID in /etc/hosts

I'd like to setup a static hostname for an IPv6 address on local network. It seems, however, that /etc/hosts won't accept a zone ID - when I append a zone ID to an IPv6 address, it acts as if the host ...
4
votes
3answers
633 views

General Linux support for IPv6 ready?

From an end user perspective, what needs to be, and have been done, by developers to support IPv6 in the Linux kernel and Linux distributions? In other words, when (and if) someday the worlds ...
4
votes
2answers
807 views

Convert MAC address to Link-local address with bash

How can I convert a Mac address into an ipv6 Link-Local address? you have to add fe80:: at the start and insert ff:fe in the middle furthermore all leading zeros must be stripped
4
votes
2answers
3k views

How to disable IPv6 on OpenBSD?

I'm sure that in my network I will not use IPv6 only IPv4. So according to the KISS principle I will need to disable it. How can I do it? OS is OpenBSD 5.1.
4
votes
3answers
3k views

Why does SSH show protocol as tcp6 *and* tcp in netstat?

$ netstat -nat Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:80 ...
4
votes
3answers
3k views

DHCPv6 prefix delegation server for linux?

What linux DHCPv6 client can I set up so it requests a prefix on one interface and then on all the other interfaces it will give out addresses (or if requested, a smaller prefix delegation)? It would ...
4
votes
1answer
2k views

Inability to use IPv4-mapped IPv6 on debian squeeze

I have a squeeze box that I'm testing ipv6 on... eth3 is the interface... if I set up an 'normal' ipv6 address (::101:c0a8:3132/120), I see expected results in ifconfig... eth3 Link ...
4
votes
2answers
446 views

IPv6 connections timeout

I'm having issues with IPv6 connections. Only with those. They timeout roughly every 10 minutes (due to address renewal i suppose). Happens with every debian based flavour of linux i tried in a year ...
4
votes
1answer
654 views

tproxy per user

I'm in the process of adding some parental control to my box (http filtering), but I'm something of a nOOb when it comes to network configuration :-( The box is used by the whole family (one account ...
4
votes
1answer
532 views

Control source address for whois queries

is it possible to execute the command "whois" and choose the outgoing ip for the query? I have mounted several IP's on my network interface "/etc/network/interfaces" for ssl porpuses, but would be ...
4
votes
1answer
92 views

How can I resolve MAC knowing ipv6 addr w/o ip command?

I installed OpenWrt on my router and I wanted to get MAC address of some machine connected to it. With ipv4 I would use arp command. But I want to resolve HW address knowing ipv6 addr. I have read ...
4
votes
1answer
123 views

putting extra hops into traceroute6 on OpenBSD

I'm running OpenBSD, or maybe FreeBSD. I don't have lots of IPv4 addresses to waste, but who doesn't have a few billion of IPv6 ones? How do I add some extra IPv6 hops to a traceroute6, around pf(4) ...
3
votes
5answers
3k views

Curl with ipv6 not working by default

I am trying to curl ipv6 addresses, but without success. If I try lets say: curl https://google.com I wait for a timeout and get network unreachable If I force ipv4, everything is fine. ...
3
votes
2answers
4k views

netstat — why are IPv4 daemons listening to ports listed only in -A inet6?

I have a computer with: Linux superhost 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64 GNU/Linux It runs Apache on port 80 on all interfaces, and it does not show up in netstat -planA inet, ...
3
votes
2answers
7k views

SSH login via IPv6 successfull while using IPv4 to the same host yields “Permission denied”

I'm currently stumped by a strange problem… I have a dual stack host to which I want to SSH. If I connect via IPv6 everything works like expected datenwolf@foo ~/ > ssh -6 bar.example.com ...
3
votes
1answer
3k views

How to configure an OpenWrt 10.03 router to forward an IPv6 connection to the clients?

So I have a TL-WR1043ND router with OpenWrt 10.03 on it. I have clients connected to it through the LAN ports. My ISP provides me a /64 IPv6 block, and I'm using PPPoE authentication. How can I ...
3
votes
1answer
643 views

Kernel /proc ipv6 settings precedence

I'm about to connect our network to the IPv6 Internet and need to control the kernel ipv6 settings found under /proc. I know there are configurations for each interface, for all interfaces, and the ...
3
votes
2answers
522 views

Linux: Is there a IPv6 equivalent to the IPv4 kernel option accept_local?

Since linux kernel >= 2.6.33 the kernel option "accept_local" can be modified: /proc/sys/net/ipv4/conf/${interfaceID}/ accept_local - BOOLEAN Accept packets with local source addresses. ...
3
votes
1answer
1k views

arping equivalent for IPv6

What is an equivalent for IPv6 of arping -q -c 3 -A -I [device] [ip]? I know, there is not an arp in IPv6 and Neighbor solicitation used instead, but which linux user space tool can send such ...
3
votes
2answers
1k views

IP rule for IPv6

When I try to add an IP rule for IPv6 on my Linux system, it errors out: $ ip -6 rule add fwmark 0xfab lookup 0xf RTNETLINK answers: Address family not supported by protocol I checked out the IP ...
3
votes
0answers
48 views

Linux Routing Question

I was wondering how it would be possible to have multiple IPv6 default gateways on CentOS linux. I currently have two interfaces with IPv6 (venet0 and tb0), both with different blocks routed to them. ...
3
votes
1answer
189 views

Why is my DAD slow?

The last few boots of my Arch Linux, I noticed I had no network access. I'm using a netctl profile to give my adapter a static IPv4 address, which by itself works fine. So I had a look at the logs, ...
2
votes
2answers
3k views

How to check if IPv6 is enabled on a Debian Linux?

Can one disable the IPv6 stack on Debian Linux, especially Wheezy? If so how do I know if it's disabled on a system?
2
votes
3answers
2k views

How to check a Fedora system if IPv6 is disabled or not?

I remember that some distribution installers asked in the past if IPv6 should be enabled or not. Perhaps the Fedora installer did (or does) it as well. How do I easily check a Fedora system (>= 17) ...
2
votes
1answer
160 views

Manually configure ipv6 address in 2 different subnets

I have a following setup Linux1---------------Linux2------------------Linux3 (eth0) (eth1) (eth0) (eth0) I have this in a local network i.e the Ethernet cables are ...
2
votes
1answer
1k views

Netcat (nc6) - Minimal IPv6 only TCP Server and Client

Im am trying to set up a basic IPv6 only echo-server using netcat (or rather nc6). Client and server are both in the same local network. However, the client quits immediately: IPv6-Server: $ nc6 ...
2
votes
1answer
4k views

How to add ipv6 default route

I have the following setup Linux 1 Linux 0 eth1 eth0-------------------eth0 14.14.14.80 19.19.19.20 19.19.19.10 2005::5/64 ...
2
votes
1answer
95 views

Why is ping6 using IPv4 socket?

I enabled IPv6 in a CentOS 7 server and everything is working as expected, except for ping6: it is showing 3-5 delays between requests (but the RTT is fine): $ ping6 www.google.com <...5 ...
2
votes
2answers
1k views

How do I set up an IPv6 tunnel in Fedora?

I have been experimenting with IPv6. Hurricane Electric through their http://tunnelbroker.net service offer a free IPv6 tunnel. I would like to be able to use this reliably on my Fedora 14 desktop ...
2
votes
1answer
246 views

Make a linux network device a router

I am developing an IPv6 network device driver. It should behaviors like a router, i.e. send router advertisement regularly. But now my device is working like a node, send router solicitation. What ...
2
votes
1answer
3k views

How to make IPv6 static routes persistent on CentOS?

Static routes are forgotten once the network service is restarted. However, IPv4 static routes can be made persistent by adding them to /etc/sysconfig/static_routes. This file is read by the network ...
2
votes
1answer
295 views

How to set up the server to use IPv6 network

I have a server which is able to connect the network through IPv6 tunneling. I want to use it as a proxy server. I have to things to understand: How to set up the DNS? Is there any open DNS that ...
2
votes
2answers
111 views

How can I add an IPv6 gateway?

For example: ip -6 route show | grep ^default There is no output. So there's no default gateway for IPv6. also I see some complains from the kernel side of things: dmesg | grep IPv6 eth0: no ...
2
votes
1answer
257 views

How do I create an IPv6 overlay network?

I would like to create host-only IPv6 networks on two hosts and then route between them. On each host, there will be a dummy interface, at ipv6_prefix::9. I would like to be able to ping that ...
2
votes
2answers
123 views

Force IPv6 only through Miredo

I have an Ubuntu PC with Miredo's implementation of the Teredo protocol. I want to temporarily make it so that I can access IPv6-only addresses with all IPv4 networking available solely for Miredo to ...
2
votes
2answers
243 views

IPv6 NDP timer problem

Need to change Fedora Linux's IPv6 stack for NDP DAD timer changes. How to locate the Fedora's IPv6 and IPv4 stack in Fedora distribution dvd/site so that, we can recompile and generate new stack ?
2
votes
1answer
602 views

Can't get Hurricane Electric IPv6 tunnel to work on Fedora

I have recently moved to a university where all computers get a public IPv4 address. Since the teredo tunnel I was using doesn't work anymore and I have a public address, I am wanting to use Hurricane ...