Bug 71505

Summary:	configuring rp_filter for an interface that is added after boot
Product:	[Retired] Red Hat Linux	Reporter:	D. Hugh Redelmeier <hugh>
Component:	initscripts	Assignee:	Bill Nottingham <notting>
Status:	CLOSED WONTFIX	QA Contact:	Brock Organ <borgan>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	7.3	CC:	hugh, rvokal
Target Milestone:	---
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Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:	2005-09-29 20:13:51 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description D. Hugh Redelmeier 2002-08-14 15:02:02 UTC

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Description of problem:
/proc/sys/net/ipv4/conf/eth0/rp_filter controls the (poorly documented) reverse
path filter feature for eth0.  The user can control this through
/etc/sysctl.conf, but sysctl(8) is only run automatically at boot time.  Since
interfaces are brought up at other times, the right control would be a new
variable within /etc/sysctl/network-scripts/ifcfg-*. ifup should implement this.


Version-Release number of selected component (if applicable):
initscripts-6.67-1

How reproducible:
Always

Steps to Reproduce:
On a notebook with eth0 on a PCMCIA card
On a notebook where eth0 is a PCMCIA card:
1.in /etc/sysctl.conf, place "net.ipv4.conf.eth0.rp_filter = 0"
  but leave net.ipv4.conf.default.rp_filter = 1
2.reboot machine
3.insert eth0
4.examine /proc/sys/net/ipv4/conf/eth0/rp_filter.  It will be 1 but should be 0.
	

Actual Results:  /proc/sys/net/ipv4/conf/eth0/rp_filter is 1

Expected Results:  /proc/sys/net/ipv4/conf/eth0/rp_filter is 0

Additional info:

rp_filter should be better documented.  It does not seem to be mentioned in the
man pages.  It is described in the kernel source files:
Documentation/filesystems/proc.txt Documentation/networking/ip-sysctl.txt

Comment 1 Bill Nottingham 2005-09-29 20:13:51 UTC

Closing bugs on older, no longer supported, releases. Apologies for any lack of
response.

Realistically, the best way to support this is probably via a udev rule on
device creation in current releases.