trevor at tecnopolis.ca
Thu Jan 2 01:15:55 CST 2014
Yet another obscure problem. /etc/dhcp/dhclient-exit-hooks is supposed to
run (if it exists) after dhclient has accepted a new DHCP IP from your ISP
and done all its stuff. One would assume that would include setting the
IP on your actual interface.
I have a problem where a script that /etc/dhcp/dhclient-exit-hooks talks
to (async through a named pipe, so after that it won't block) then does
some stuff based on what /sbin/ip says the ip address is. I am expecting
this to be the *new* ip address. But what it seems to be doing is still
using the old ip, meaning (if I'm following my extremely complex scripts
properly) /sbin/ip is still returning the old ip at that point.
Does anyone have experience with dhclient, or its hooks? Is this even
possible? Even weirder is my scripts wait an additional 10s before
checking /sbin/ip so even if there was a short delay, it shouldn't still
give me the old ip.
The /sbin/ip command I use it:
/sbin/ip -o -4 addr list <interface>
then I parse out the address.
Is there anything in the linux networking layer that would cause an IP
bind to "not show up" for >10s?
Secondly, debug testing this will be very difficult because our Shaw IP's
change so infrequently. I suppose I could "trick it" by switching NICs
and/or changing my NIC's MAC. I've never done that before, is that easy
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