Duplicate ipv6 global 2001 address issue . Redhat

IPV6 test case

If we set a static ipv6 and IPV6_AUTOCONF was set to yes. the IPV6_AUTOCONF value will not take affect until we bring down the interface and bring it back up. Performing a network restar will not change the value of IPV6_AUTOCONF.. We have found that after a restart of the network service. The interface receives a second global 2001 address.

steps to duplicate

1. Add IPV6ADDR=
2. IPV6_AUTOCONF=yes change to no
3. restart the network manager or service

4. if you want to set the default gW use IPV6_DEFAULTGW= . This may be requires as router advertisements will be disabled. RA is required to received the GW information from the router.

Possible fix is to restart the interface or the below.
Set net.ipv6.conf.eth0.accept_ra to on in the sysctl file and set autoconf to off.

net.ipv6.conf.eth0.autoconf = 0

net.ipv6.conf.eth0.accept_ra = 1 << enable router advertisments /sbin/sysctl -a | grep net.ipv6.conf. << check settings

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DNS RFC References

:RFC standard for naming host names

2.1 Host Names and Numbers

The syntax of a legal Internet host name was specified in RFC-952
[DNS:4]. One aspect of host name syntax is hereby changed: the
restriction on the first character is relaxed to allow either a
letter or a digit. Host software MUST support this more liberal

Host software MUST handle host names of up to 63 characters and
SHOULD handle host names of up to 255 characters.

Whenever a user inputs the identity of an Internet host, it SHOULD
be possible to enter either (1) a host domain name or (2) an IP
address in dotted-decimal (“#.#.#.#”) form. The host SHOULD check
the string syntactically for a dotted-decimal number before
looking it up in the Domain Name System.

Other references


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