Update: booting using sysrescuecd, I removed the
/etc/rcS.d/S13networking link and rebooted into single-user mode. It
completed OK, so I then ran /etc/init.d/networking start, which
exhibited the same problems it did when run by init. However this time
I was able to kill the process, at which point I noted the network had
been started. Exiting from the single-user mode allowed the boot to
continue to a normal command prompt.
This still leaves me with the problem of not being able to reboot the
computer remotely, since the workaround involves disabling the network.
dmesg shows the following from the last boot:
[ 181.805309] r8169 0000:03:00.0: firmware: agent loaded
rtl_nic/rtl8168e-3.fw into memory
[ 181.917202] r8169 0000:03:00.0: eth0: link down
[ 181.920948] r8169 0000:03:00.0: eth0: link down
[ 181.928316] ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 184.284849] r8169 0000:03:00.0: eth0: link up
[ 184.292178] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 195.016023] eth0: no IPv6 routers present
The eth0: link becomes ready line is the last line I get on the screen
when I boot into single-user mode with networking enabled.