[ILUG] intermittent IP failure

[Kae Verens]

recently I've had to have a few extra IPs assigned to my machine in 
order to handle SSL certs.

The IPs connect okay, but then after a random amount of time, they start 
to fail.

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

again, the symptom is that I cannot ping the .228 IP address from 
outside the machine itself.

In webmin (yes, yes...), I navigate to network interfaces, open up 
eth0:4 and simply click "save and apply" without changing anything, and 
suddenly everything works.

This is getting annoying, as the failures appear to be random, and I 
can't guarantee that an IP will be available for any particular time.

Has anyone got any idea what to look for? I currently have a three other 
addresses experiencing the same problem, so will be able to perform 
three tests.

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