W7 IPv6 connectivity problems due to Cisco IOS bug

[nickbeee]

Moved here from another section as it's W7 related.

Nick do you have any more specifics on those issues? We've been running windows 7 with router advertisements for a couple of years now and haven't had any issues.

I've got one W7 (Pro, 64bit, SP1) test machine at the office so my (IPv6) experiences of this OS are very limited compared to yours.

The router is a Cisco 871 which is configured for SLAAC and uses DHCPv6 to provide the DNS server. The W7 client configures itself correctly for EUI-64 address, sets it's gateway correctly and picks up the DNS server. However, it suffers from intermittent ipv6 connectivity. Other (FreeBSD and Linux) hosts on the same router work correctly.

Solved: Turned out to be a Cisco IOS bug rather than W7. Starting with IOS version c870-advipservicesk9-mz.124-15.T12.bin the original router firmware...

I ran debug ipv6 nd and debug ipv6 dhcp detail. I saw plenty of ND activity but zilch on the dhcpv6.

I then upgraded the IOS to c870-advipservicesk9-mz.124-24.T6.bin (the most recent version available from Cisco) and repeated.
Lots of DHCPv6 activity, DNS server assigned and IPv6 connectivity seems solid. I can only conclude that something is broken in that earlier IOS version.

Code Select Expand


Jan 25 21:05:07.400: IPv6 DHCP: Received INFORMATION-REQUEST from FE80::1AA9:5FF:FEF0:7962 on Vlan101
Jan 25 21:05:07.400: IPv6 DHCP: detailed packet contents
Jan 25 21:05:07.400:   src FE80::1AA9:5FF:FEF0:7962 (Vlan101)
Jan 25 21:05:07.400:   dst FF02::1:2
Jan 25 21:05:07.400:   type INFORMATION-REQUEST(11), xid 13959647
Jan 25 21:05:07.400:   option ELAPSED-TIME(8), len 2
Jan 25 21:05:07.400:     elapsed-time 0
Jan 25 21:05:07.400:   option CLIENTID(1), len 14
Jan 25 21:05:07.400:     000100011512AFEC18A905F07962
Jan 25 21:05:07.400:   option VENDOR-CLASS(16), len 14
Jan 25 21:05:07.400:   option ORO(6), len 8
Jan 25 21:05:07.400:     DOMAIN-LIST,DNS-SERVERS,VENDOR-OPTS,INFO-REFRESH
Jan 25 21:05:07.404: IPv6 DHCP: Option VENDOR-CLASS(16) is not processed
Jan 25 21:05:07.404: IPv6 DHCP: Using interface pool V6-LAN101
Jan 25 21:05:07.404: IPv6 DHCP: Sending REPLY to FE80::1AA9:5FF:FEF0:7962 on Vlan101
Jan 25 21:05:07.404: IPv6 DHCP: detailed packet contents
Jan 25 21:05:07.404:   src FE80::FEFB:FBFF:FEEA:1727
Jan 25 21:05:07.404:   dst FE80::1AA9:5FF:FEF0:7962 (Vlan101)
Jan 25 21:05:07.404:   type REPLY(7), xid 13959647
Jan 25 21:05:07.404:   option SERVERID(2), len 10
Jan 25 21:05:07.404:     00030001FCFBFBEA1727
Jan 25 21:05:07.404:   option CLIENTID(1), len 14
Jan 25 21:05:07.404:     000100011512AFEC18A905F07962
Daisy_35#
Jan 25 21:05:07.404:   option DNS-SERVERS(23), len 16
Jan 25 21:05:07.404:     2001:470:20::2


[antillie]

Well the "T" in the IOS file name unofficially stands for "trouble" as it indicates that that image is part of a development (ie: beta) train. If stability is a serious concern then never use a "T" release.