Re: [Cooker] DNS Resolution failed again, but in a strange fashion, after last cooker update

[Frank Griffin]

Steve Morris wrote:
> Frank Griffin wrote:
> > Steve Morris wrote:
> > > Why did it work under tty but not under X?
> > The better question is why it stopped working when you rebooted.  I 
> > assume you verified that other usage of DNS (besides Thunderbird) was 
> > affected, and checked all the stuff mentioned in your other thread ?
> Sorry Frank, I hadn't. When I got the issue, I went straight into the 
> network configuration via network manager to check it, found that I 
> still had the dns address hardcoded as the modems ip address (I hadn't 
> switch back to resolving it from dhcp yet),  exited the configuration, 
> disconnected then reconnected to eth0 and Thunderbird was then 
> immediately able to retrieve mails from the isp.

If that's the case, either your router is defective (and a DHCP 
reconnect cleared it up), or something messed up your resolv.conf or 
routing table, and recycling the interface recreated it.

Read the man page for the route command, and you might want to get 
yourself a good book on Unix networking (the O'Reilly TCP/IP book is 
pretty decent).  "route -n" will print your current routing table, and 
the book will tell you how to read it.  Basically, you go through the 
entries and select the most specific one which matches the IP address to 
which you're trying to send, see where that tells you to send the 
packet, and if it's not a specific IP address or an interface name, take 
whatever it is and start over until it is.  If you get lost, the stack 
is probably getting lost as well.

That's if the routing table is messed up.  You should be able to tell by 
now if resolv.conf was messed up.

You really shouldn't be running cooker on a system that has to be 
working NOW.  Cooker assumes that you can either fall back to something 
else in order to preserve diagnostic info, or that you are capable of 
recording all relevant diagnostic info before hacking the system to 
correct the problem, which can wipe all the fingerprints and remove all 
traces of DNA that would allow us to figure out what happened.

If you want to actively test cooker, you might consider getting another 
or a bigger harddisk on which you can define one or more test partitions 
which have exactly as many sectors as your active cooker partition.  
Then, if you hit an error situation, use dd to copy your active 
partition to one of these.  As long as the number of sectors is 
identical, the copy should give you something that can be mounted from 
your working system.  A little tweaking of your bootloader will allow 
you to boot one or the other.