Comment 11 for bug 284874

Having the same issue on Lucid:

ar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 1 of 5 (Device Prepare) scheduled...
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 1 of 5 (Device Prepare) started...
Mar 30 11:27:34 tthomas NetworkManager: <WARN> nm_ip6_device_new(): eth0: error reading /proc/sys/net/ipv6/conf/eth0/accept_ra: (4) Failed to open file '/proc/sys/net/ipv6/conf/eth0/accept_ra': No such file or directory
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 2 of 5 (Device Configure) scheduled...
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 1 of 5 (Device Prepare) complete.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 2 of 5 (Device Configure) starting...
Mar 30 11:27:34 tthomas NetworkManager: <info> (eth0): device state change: 4 -> 5 (reason 0)
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 2 of 5 (Device Configure) successful.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 3 of 5 (IP Configure Start) scheduled.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 2 of 5 (Device Configure) complete.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 3 of 5 (IP Configure Start) started...
Mar 30 11:27:34 tthomas NetworkManager: <info> (eth0): device state change: 5 -> 7 (reason 0)
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP4 Configure Get) scheduled...
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Beginning IP6 addrconf.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 3 of 5 (IP Configure Start) complete.
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP4 Configure Get) started...
Mar 30 11:27:34 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP4 Configure Get) complete.
Mar 30 11:27:45 tthomas NetworkManager: <info> Device 'eth0' IP6 addrconf timed out or failed.
Mar 30 11:27:45 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP6 Configure Timeout) scheduled...
Mar 30 11:27:45 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP6 Configure Timeout) started...
Mar 30 11:27:45 tthomas NetworkManager: <info> (eth0): device state change: 7 -> 9 (reason 5)
Mar 30 11:27:45 tthomas NetworkManager: <info> Marking connection 'Auto eth0' invalid.
Mar 30 11:27:45 tthomas NetworkManager: <info> Activation (eth0) failed.
Mar 30 11:27:45 tthomas NetworkManager: <info> Activation (eth0) Stage 4 of 5 (IP6 Configure Timeout) complete.
Mar 30 11:27:45 tthomas NetworkManager: <info> (eth0): device state change: 9 -> 3 (reason 0)
Mar 30 11:27:45 tthomas NetworkManager: <info> (eth0): deactivating device (reason: 0).

Of note is that I don't have an entry for eth0 under:
/proc/sys/net/ipv6/conf/etho/accept_ra

I do under all and default, which from my dealings with fedora should be used in cases where there aren't device specific settings.