IPv6 is the successor to IPv4. Rather than 2^32 addresses (like IPv4), it has 2^128, which is 340,282,366,920,938,463,463,374,607,431,768,211,456 unique addresses (34 undecillion). IPv6 addressing is quite different to IPv4 and is not backwards compatible, but protocols that sit on top (HTTP, SSH, ...

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15 views

Connect with ipv4 to server with Openvpn and continue with ipv6 to other server [on hold]

I want to connect to my Openvpn server with ipv4 and then connect from the server with ipv6 to another server (this one only has ipv6). How can I do this? I run an Ubuntu 16.04 server with Openvpn ...
0
votes
0answers
54 views

IPv6 not working

I'm unsure as to why this is happening... anyway, let me start from the beginning The Setup 1 * Dedicated server with a /29 IPv4 and /48 IPv6 (from Nocix (DataShack)) 1 * CentOS 7 KVM host 1 * ...
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votes
0answers
24 views

How does this IPV6 route work?

I'm currently learning IPV6 and it seems that it's not only that the addresses get longer ;-) I have a quick question: When I do a netstat -r on a BSD router that I have here (which is IPV6 enabled) I ...
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votes
0answers
53 views

IPV6 suddenly stopt working?

Right now I have two Linux servers(CentOS 7.2.1511 (Core)) that are identical, but on one the server stopped connection to ipv6. EDIT Also, forgot to mention that I added the Google DNS in, ...
0
votes
0answers
22 views

6in4 Tunnel with /80 Addresses

I want to setup my own 6in4 tunnel server on CentOS 7, my VPS ISP can only provide a /80 IPv6 block addresses while I can see most of tutorials said it requires /64 for client's DHCP server to work. ...
0
votes
0answers
18 views

Can't reach centos server after “Multicast listener report” IPV6

I ran into a problem that occurs only on a few servers. Every 5-6 minutes I lose connection to the server, and it get backs after a few minutes. In most cases it's a VM that is not reachable while ...
1
vote
2answers
32 views

Debian / IPv6: Default route expires after 1800 secs, loosing connectivity

I'm running Debian 8 on a vServer. After installing docker and enabling IPv6 i noted something strange. I don't know if docker has anything to do with this, it's just that i noticed this problem after ...
0
votes
0answers
5 views

Ubuntu as a IPv6 router not taking default route from upstream RA [migrated]

I've got an Ubuntu 14.04 box that acts as my home router. I've got an IPv6 /64 delegated by my ISP, and I'm using RA and the WIDE DHCPv6 client to configure IPv6. Everything works well, except no ...
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votes
1answer
66 views

“Ipcalc -n ipv6_addr” command is giving error

I am trying to calculate network address of Ip address by using Ipcalc command. when i am using ipcalc -n ipv4 address,then it is running fine and give the network address for the IPv4. But when i ...
0
votes
1answer
25 views

Allow outgoing IPv6 connections for VPN clients

I have the OpenVPN server. A client connecting to this server receive an internal IPv4 address (10.2.52.X) and an external IPv6 address. I need to perform a masquerading (NAT) for IPv4 but I don't ...
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votes
1answer
56 views

Building router with one ethernet interface

Good day! I have 2 servers in datacenter and I want to use one of them as router for another instead of default gateway provided by DC. Both servers have one ethernet interface called 'eth0' with ...
0
votes
0answers
26 views

IPv6 interface not responding to neighbor solicitations, DHCP involved too

ip addr shows: 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 02:6d:5e:86:29:49 brd ff:ff:ff:ff:ff:ff inet ...
0
votes
1answer
84 views

Hyper-V vm can ping host but host cannot ping Hyper-V vm?

When ping host from hyper-v VM, it works both with ipv4 or ipv6. Pinging MyHost [fe80::3549:ee49:a75c:619c%9] with 32 bytes of data: Reply from fe80::3549:ee49:a75c:619c%9: time<1ms Reply from ...
0
votes
0answers
17 views

Kamailio as TCP-only SIP register and relay

I have a rather complicated setup in which I'd like to run a SIP server. In general, I want to run an IPv6-only Kamailio SIP-server on internal network and have outside SIP-clients be able to make ...
0
votes
0answers
47 views

IPv4/IPv6 dualstack setup in Debian/Ubuntu via preseed

I use preseed to provision my Ubuntu 16.04 installation. It has the following options to set up IPv4 or IPv6 address # Static network configuration. # # IPv4 example #d-i netcfg/get_ipaddress string ...
1
vote
1answer
37 views

How to redirect traffic through IPv6 IPSec (strongswan) gateway?

I'm trying to set up IPSec secured connection to the gateway. Have three hosts: A: eth1 - fec0:1::1/64 B: eth1 - fec0:1::2/64 eth2 - fec0:2::2/64 which is gateway between A and C; forwarding is set ...
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votes
0answers
24 views

How does AWS convert an IPv6 address to an IPv4 address when whitelisting “My IP” address [migrated]

I recently had to whitelist my IP address in an AWS security group using the "My IP" option. It worked perfectly and displayed an IPv4 address, but when I looked up my IP address with Google I got an ...
1
vote
1answer
227 views

OpenSSH adds <IPv6>%2 to known_hosts

When I connect to a CentOS 7 host with IPv6 my ssh client always adds <IPv6 host addr>%2 to known_hosts even though the host key for this host (with the host's IPv6 address) is already present ...
17
votes
2answers
1k views

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 ...
1
vote
1answer
38 views

IPv6 and ESP as a next header

I'd like to know how to parse IPv6 header and get offset to TCP header and its payload. I know that IPv6 has fixed base header. I know also that there are several extension headers in IPv6 - among ...
1
vote
0answers
20 views

Delayed Ping of a link-local address with Windows 7/Server 2008 R2/Server 2012 R2

I have a strange effect here, which I do not understand. PS C:\Users\user1> ping fe80::219:bbff:fe0e:c600%16 -t Ping wird ausgeführt für fe80::219:bbff:fe0e:c600%16 mit 32 Bytes Daten: Zielhost ...
0
votes
0answers
12 views

What changes with Kerberos Authentication in IPv6 when using NAT? [duplicate]

How should Kerberos Authentication be setup with IPv6? Of you're using NAT for IPv6 where there is a single public IPv6 address and it translates to the machines inside in the ULA range?
0
votes
1answer
25 views

What changes with Kerberos authentication in IPv6 when everyone has a public IPv6 Address?

How should Kerberos authentication be set up with IPv6? What implications are there when client devices each use a public, globally routeable IPv6 IP address? What changes when setup this way ...
0
votes
1answer
76 views

Firewalld blocks IPv6, ignores config

I'm trying to setup an IPv6 web-server on CentOS 7.2 with NGINX. I have tested my IPv6 connectivity outgoing and incoming - everything works. My IP, AAAA records, etc as fine as well. Essentially ...
0
votes
0answers
26 views

Allow outgoing traffic behind ipv6 firewall behind router

I am working on configuring ipv6 traffic for a project and I am running into a problem. When I try to ssh from the machines that are behind the router into the router, it blocks the connection. I ...
2
votes
1answer
54 views

Can Linux be made to honour IPv6 Route Advertisement preferences?

Bottom Line Up Front: I can't get a Linux box receiving RAs to use the RFC4191 "Default Router Preference" value to prefer higher-priority routes. Instead, whichever default route it learnt first is ...
1
vote
0answers
44 views

IPv6 Routing // Destination unreachable: Beyond scope of source address

I want to setup Dual Stack on Customer VMs. The Router is a VM too. Running on Debian Wheezy. Overall virtualized by ESXi. IPv4 is working fine. Ping from Customer VM ping6 -c 1 heise.de PING ...
0
votes
1answer
36 views

Linux host does not retransmit with a lower packet size in response to ICMPv6 Packet Too Big message

I'm seeing this in Wireshark when curling this URL: On the same network, a Windows host retransmits properly, but an Android host does not. On a different network (presumably appropriately ...
0
votes
0answers
52 views

IPv4 over IPv6 IPsec tunnel

I've got two Cisco 2811 routers, both with a global static IPv6 adress, and an IPsec tunnel between them (using VTIs). Is it possible to send IPv4 traffic over this tunnel? The relevant parts of the ...
0
votes
1answer
36 views

How to force Centos to use ipv6 interface only?

My Centos server has two virtual (Openvz) interfaces. One from these interfaces has ipv4 address configured, while the other one has the ipv6 one. In short this server is used for browsing / proxy. ...
1
vote
1answer
17 views

Manually Assigning Site Local IPv6 Multicast Address to DHCP Server

According to https://en.wikipedia.org/wiki/IPv6_address#Multicast_addresses, ff05::1:3 is a site local multicast address for All-dhcp-servers. Based on this, when I add the DHCP role to a Windows ...
1
vote
0answers
12 views

Assigning Prefix-Flexible Static IPv6 Addresses to Servers

Sometimes it's desirable to assign a server a static IPv6 addresses. Hand-configuring a static global unicast IPv6 address is one way to do this but necessitates manual updating any time the address ...
0
votes
0answers
54 views

Ensure systemd wait for IPv6 before start service unit

When I have a service listening on a specific IPv6 address, it fails on boot, claiming that the address is still not available. This happens to every service that is listening on specific addresses. ...
1
vote
1answer
85 views

SOA record in AAAA query reply when IPv6 is not supported

When I do dig AAAA to a website that doesn't support IPv6 yet, the reply has an SOA record. Is it a requirement to have the SOA record in response to a AAAA query when the service doesn't support ...
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votes
1answer
70 views

IPv6 + PTR + gmail returning error

I have a problem with mail connected to gmail account. Every time when i wanna send mail i got that error: Our system has detected that this message does not meet IPv6 sending guidelines regarding ...
0
votes
1answer
55 views

AWS ELB with ipv6 fails on online tests

I have an ELB with ipv6 AAAA DNS configured on route 53. The problem is that the tests I used tell me it's not ok (I don't have an ipv6 connection for testing): AFAIK I don't need to configure ...
0
votes
0answers
27 views

IPv6 Ping is unsuccessful when IP is obtained from DHCP server

I just faced this problem and it's driving me crazy. I have DHCP server for both IPv4 and IPv6. IPv4 works like a charm but the problem is IPv6. My client gets IPv6 (fc50::a9 to be exact) from DHCP ...
0
votes
0answers
30 views

Very slow outgoing requests, from **some** servers

In this case, it's an HTTP request to https://www.instagram.com/, but it has happened before like this. From my home (Ubuntu, i686) server it's very fast (~ 0.3 sec). From my online, modern (Ubuntu, ...
0
votes
0answers
67 views

IPv6 is not working between two OpenWRT devices

I have 2 problems lately regarding IPv6: My ISP doesn't provide an IPv6 prefix (even with modem in bridge, and yes the ISP supports) so, I'm using SIXXS tunnel , it doesn't attribute IPv6 to another ...
0
votes
0answers
64 views

How to avoid curl trying IPv6 name resolution

From a docker container when I try to curl 'another container name', curl first tries to resolve the name to IPv6. This causes few seconds delay because the web server is not reachable over ipv6. I ...
0
votes
0answers
166 views

IPv6: Destination unreachable: Address unreachable

My server can't ping/reach any other outside. ping6 works for my local fe80::468... address as well as the 2a01:4f8..., but not for fe80::1! Errors/Troubles/Issues: ip neigh show fe80::1 dev eth0 ...
0
votes
0answers
60 views

HAProxy configuration problems (with source directive)

I have HAProxy setup to listen on a public IPv4 address (1.2.3.4), it is supposed to proxy all requests to my b_http backend. The back-end has a source line that makes it connect to the server/site ...
2
votes
0answers
56 views

Is it possible to configure HAProxy to listen on IPV4, but send the request using IPV6? [closed]

Trying to configure HAProxy to listen for requests on port ipv4(Port 80) but proxy the request through eth1 to a server using ipv6. The request must be show the ipv6 address for the request. We don't ...
0
votes
2answers
42 views

IPv6 DNS Connectivity through IPv6

My clients are using IPv4 in the USA. Their ISP is not ready for IPv6 yet. My public web server is on only IPv6. It is registered with a DNS Provider(GoDaddy) that is IPv4 and IPv6 enabled. Can my ...
0
votes
1answer
39 views

Fixed Size of IPv6 SLAAC

My confusion with IPv6 SLAAC is that the router provides the network prefix, and the host generates its own part using EUI-64, which means it is always going to be a 64-bit address. Now, SLAAC is ...
1
vote
1answer
57 views

Understanding IPv6 Address

My IPv6 address is like this (some digits changed): 2001:569:78f0:ca00:bcaa:d016:4 ...as reported by whatismyipaddress.com. This is strange because I understand that there should be eight blocks ...
1
vote
1answer
89 views

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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votes
1answer
85 views

How to add IPv6 /64 block to lo (local) interface permanently

I'm using this command line to add /64block IP range to lo network interface. ip route add local 2001:bc8:1234:abcd::/64 dev lo But, when I'm reboot my server. It requires again to execute that ...
1
vote
0answers
33 views

Multiple IPv6 addresses added to interface, now IPv6 not working on my server [duplicate]

I got /64 IPv6 block from my server provider. When I add few IPv6 addresses (maybe 10 or 20) to network interface. Everything works fine about IPv6 network. When I'm added above 500+ IPv6 addresses ...
0
votes
1answer
155 views

Nginx proxy_pass always sending to [::1]

I am having problems with redirection from Nginx to gunicorn. I'm using proxy_pass to redirect to https://127.0.0.1:5000, and yet the redirect is being sent to https://[::1]:5000. Here is my own ...