Nope. No errors being logged.
Strange. Can you set DHCLIENT_DEBUG to "yes" in /etc/rc.config.d/dhcpcd.rc.config and restart the network? And, as I'm still not clear about what your situation is when the network is "down", can you check 'ifconfig -a' in such a case? Ping your own address? And in addition look for messages like "transmit timeout" or similar messages in /var/log/messages that might come from the driver?
When the network is "down", it seems as though I can't resolve other hosts. For example, I can ping my own IP address all I want, and get fine results. Pinging other addresses, though, even internal ones on my own LAN, fails every time (until I restart dhcpcd, that is). I get a "Destination Host Unreachable" message after every packet attempt. One strange thing, though: take a look at the first line of ping's output, where it says, for example: "PING coloradocollege.edu (205.170.1.68) from 205.170.13.166 : 56(84) bytes of data." So, it looks like it's getting an IP addresss for the remote host, it just can't get there. What the heck is going on here? Regarding the next question, "ifconfig -a" looks normal (I've still got an IP address, and other stuff seems to be set properly). That is, it looks the same when my network is working and when it isn't. Also, I'm running dhcpcd with dhclient_debug set to yes, and so far am seeing no new messages.
Do you have access to the DHCP server logfiles? They could also be helpful.
No, I don't have access to those. :-(
To ultimately determine whether it is a DHCP or driver problem, try a static configuration instead of DHCP: rcdhclient stop ifconfig eth0 192.168.0.1 broadcast 192.168.0.255 netmask 255.255.255.0 up route add default gw 192.168.0.5 (or whatever the address is that you last got from the DHCP server) ...and see the problem turns up as well.
I'm a bit unclear- is "route add default gw 192.168.0.5" a second command after ifconfig? Also, which address should be used rather than "192.168.0.5"? My own computer's most recently assigned IP address? My broadcast address?
The names are utterly confusing, which is neither your fault, nor mine :)
Ain't that the truth... -SB -- "As an adolescent I aspired to lasting fame, I craved factual certainty, and I thirsted for a meaningful vision of human life -- so I became a scientist. This is like becoming an archbishop so you can meet girls." -- Matt Cartmill