OVH IPv6 OVH Setup

Guide for setting up IPv6 on an OVH dedicated server. Any additions corrections, please let me know.

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#### IPv6 ADDRESS SETUP / OVH
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IPv6 Configuration — OVH Documentation 0.0.1 documentation
FAQ - CentminMod.com LEMP Nginx web stack for CentOS

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1. Log into the OVH control panel, select server, and Manage IPs.
2. Create an IPv6 address from the block of addresses. Enter the address IPv6 address into the calculator below and it will give you the range if you need that.
IPv4/IPv6 subnet calculator and addressing planner
3. Add an AAAA record for your new IPv6 address at DNS provider (Route 53, Cloudflare, etc).
4. Open your network settings file and add IPv6 information.

Code:

# cd /etc/sysconfig/network-scripts/
# nano ifcfg-eth0

Add what is below:

Code:

IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6ADDR="xxxx:xxxx:xx:xxxx::6233/64" <-- here I'm using 6233
IPV6_DEFAULTGW="xxxx:xxxx:xx:xxff:ff:ff:ff:ff" <-- OVH gateway always has five pairs of ff(s) - see doc above.

5. Pre-emptively, we strongly suggest our customers to disable IPv6 autoconf and router advertising to prevent known issues.
Lines were already in my Centos 7 sysctl.conf file.

Code:

# nano /etc/sysctl.conf

Add or check if present:
net.ipv6.conf.eth0.autoconf=0
net.ipv6.conf.eth0.accept_ra=0

Code:

# sysctl -p

6. Restart the network, reboot, etc.

7. Pinging / Testing
Must be on a computer / server with IPv6 otherwise it won't work!

Code:

# ping6 -c4 xxxx.xxxx.xx.xxxx::6233

8. Adding to Centmin Mod

Code:

# nano /etc/centminmod/custom_config.inc

Code:

NGINX_IPV='y'

9. Follow rest of setup in FAQ #34 at FAQ - CentminMod.com LEMP Nginx web stack for CentOS

 

It was working, then I tried to combine all the information into eth0 and when I went back to eth0:0 and eth0:1, it went crazy on me giving me all kinds of errors when I did ifdown / ifup for each eth.

 

@eva2000 ended up deleting everything last night - all IPv6 addresses at OVH, all eth files on my server with excepting to eth0, all traces of IPv6. Tried it again this morning with new IPv6 addresses, got everything working.

Pings are working fine.
Testing at the website you mentioned above worked great.

The only problem I'm having is when I do an ifdown and then ifup it gives me the error below. If I do an ifup only, I get no error just a notice that the file exists. I get the error but it appears that everything is working fine.

Code:

RTNETLINK answers: File exists
ERROR    : [ipv6_add_route] 'No route to host' adding route '::/0' via gateway 'xxxx:xxxx:xx:xxff:ff:ff:ff:ff' through device ''
INFO     : [ipv6_wait_tentative] Waiting for interface eth0 IPv6 address(es) to leave the "tentative" state
INFO     : [ipv6_wait_tentative] Waiting for interface eth0 IPv6 address(es) to leave the "tentative" state

 

Also, one other thing I noticed, when viewing ifconfig I see the IPv4 addresses listed under their respected interfaces

Code:

eth0
inet xxx.xxx.xxx.xx1

eth0:0
inet xxx.xxx.xxx.xx2

eth0:1
inet xxx.xxx.xxx.xx3

But all the IPv6 addresses are listed under eth0 even though they're in the separate eth files.

Code:

eth0
inet6 xxxx:xxxx:xx:xxxx::xxx1
inet6 xxxx:xxxx:xx:xxxx::xxx2
inet6 xxxx:xxxx:xx:xxxx::xxx3

Wonder why the IPv4 are listed correctly and the IPv6's aren't?

 

Found it kind of odd, but as long as it works.