[ILUG] intermittent IP failure

[Kenn Humborg]

> As an example, I am currently trying to ping xx.xx.xx.228 and failing. 
> When I log into the machine through another IP and run ifconfig, I see 
> that it is supposedly up:
> eth0:4    Link encap:Ethernet  HWaddr xx:xx:xx:xx:xx:xx
>            inet addr:xx.xx.xx.228  Bcast:xx.xx.xx.237  
> Mask:255.255.255.240
>            UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>            Interrupt:169
> 
> when I run route, I see that it also looks right:
> Kernel IP routing table
> Destination     Gateway         Genmask         Flags Metric Ref    Use 
> Iface
> xx.xx.xx.224   *               255.255.255.240 U     0      0     
>    0 eth0
> 169.254.0.0     *               255.255.0.0     U     0      0    
>     0 eth0
> default         xx.xx.xx.238   0.0.0.0         UG    0      0     
>    0 eth0

Is that default gateway a typo?  .238 is outside the subnet .224/28.
Given that you can log into the machine remotely it's obviously
working, but if it's not a typo, I can't really see how it's working
at all.

When it's next broken, do this:

# (ifconfig ; ip route ; arp -an ) > broken-status
... use webmin to "fix it" ...
# (ifconfig ; ip route ; arp -an ) > working-status

Then diff them:

# diff -u broken-status working-status

This may provide some clues.

Later,
Kenn