[Nagiosplug-devel] [ nagiosplug-Bugs-3273915 ] Check_dhcp sends broadcast with IP instead of 0.0.0.0

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Bugs item #3273915, was opened at 2011-04-04 04:54
Message generated for change (Settings changed) made by hweiss
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Category: General plugin execution
Group: None
Status: Open
Resolution: None
>Priority: 5
Private: No
Submitted By: Jens Weibler (jensthebrain)
>Assigned to: Holger Weiss (hweiss)
Summary: Check_dhcp sends broadcast with IP instead of 0.0.0.0

Initial Comment:
check-dhcp uses an ip address from the host as source address for dhcp requests instead of 0.0.0.0
These dhcp packets get filtered by reverse path checks -> tests fails :(


check_dhcp v1991 (nagios-plugins 1.4.12)


eth0: IP XY
eth1: no IP

check_dhcp -i eth1 uses IP XY...

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Comment By: Jens Weibler (jensthebrain)
Date: 2012-10-16 06:48

Message:
The bug is still there..

From RFC 2131:
"DHCP messages broadcast by a client prior to that client obtaining its IP
address must have the source address field in the IP header set to 0."

The problem: check_dhcp.c is opening a UDP-socket. The os is setting the
source address. One solution would be to take the logic from a real
dhcpclient: using a IP-socket and set all ip-fields by hand.

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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=397597&aid=3273915&group_id=29880