Linux

Linux

Linux IPv6 routing table max_size badly dimensioned compared to IPv4

Submitted by emartell on Mon, 04/14/2014 - 17:20

http://marc.info/?l=linux-netdev&m=139352943109400&w=2

Hi everybody,

Today, a PowerDNS (open source dns, www.powerdns.com) deployment ran into
trouble with large amounts of IPv6 users. It appears a large telco 'flicked
the switch'. We had around 8000 DNS queries/s over IPv6, and everything
slowed to a crawl. 100% CPU utilization, most of it in the kernel. The same
amount of queries over IPv4 causes no problems.

Ubuntu 13.04 client doesn't get IPv6 address at boot time

Submitted by emartell on Mon, 07/01/2013 - 11:06

Problem description: an Ubuntu client doesn't configure the IPv6 address at boot time. But running manually "dhclient -6" works. dmesg reports:

[   11.997321] type=1400 audit(1372427393.005:35): apparmor="DENIED" operation="open" parent=1053 profile="/sbin/dhclient" name="/var/lib/NetworkManager/dhclient6-eth0.conf" pid=1765 comm="dhclient" requested_mask="r" denied_mask="r" fsuid=0 ouid=0

 

SLC5 and SLC6 may have IPv6 disabled

Submitted by emartell on Mon, 06/24/2013 - 16:31
  • SLC5 may have the ipv6 module disabled. Please edit the file /etc/modprobe.conf and remove the lines disabling ipv6 (#alias ipv6 off, #options ipv6 disable=1); then reboot.
  • SLC6 may have the ipv6 module disabled. Please edit the file /etc/modprobe.d/ipv6.conf and remove the lines disabling ipv6 (# options ipv6 disable=1); edit the file /etc/avahi/avahi-daemon.conf and set use-ipv6=yes; then reboot.

Manually configure static IPv6 address in SLCx

Submitted by emartell on Mon, 05/13/2013 - 14:57

Add these lines to /etc/sysconfig/network-scripts/ifcfg-eth0
IPV6INIT=yes
IPV6ADDR=2001:1458:E00C::63/64

Add these lines to /etc/sysconfig/network
NETWORKING_IPV6=yes
IPV6_DEFAULTGW=2001:1458:E00C::1

 

  • WARNING: SLC5 images have the ipv6 module disabled. Please edit the file /etc/modprobe.conf and remove the lines which disable ipv6 (#alias ipv6 off, #options ipv6 disable=1); then reboot.