Bug 214862 - Time to live (TTL) on some multicast packets incorrect using ipv6 module
Time to live (TTL) on some multicast packets incorrect using ipv6 module
Product: Red Hat Enterprise Linux 4
Classification: Red Hat
Component: kernel (Show other bugs)
All Linux
medium Severity high
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Assigned To: Neil Horman
Martin Jenner
Depends On:
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Reported: 2006-11-09 14:38 EST by Philip N. Brazell
Modified: 2007-12-10 11:07 EST (History)
2 users (show)

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Fixed In Version:
Doc Type: Bug Fix
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Last Closed: 2007-12-10 11:07:06 EST
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RHEL 7.3 requirements from Atomic Host:
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Description Philip N. Brazell 2006-11-09 14:38:02 EST
Description of problem: 
We have a local daemon process that publishes multicast heartbeats on  The ttl is hard coded into the application(JAVA) and set at 
12.  If the IPV6 module is enabled the multicast packets TTL field as 
discovered with ethereal is set to 1.  If we turn off the IPV6 module using
alias net-pf-10 off in the modprobe.conf file the ttl is then set to 15 which 
still is not correct but it allows the packet to get past the router.

Version-Release number of selected component (if applicable):
RHEL 4 Update 3, Fedora Core 3 - 5

How reproducible:

Steps to Reproduce:
1. Start the daemon process
2. Use Ethereal to sniff outbound traffic on eth0 of the box the daemon is 
running on
3. Watch the outbound packet leave eth0 and expand the IP header
4. See TTL set to 1
5. Make change listed above to the modprobe.conf - reboot
6. repeat steps 1-3
7. See TTL set to 15
8. Go to distant end (other subnet) see mcast packets arrive as expected  

Actual results:
Ethereal discovers TTL set to 1

Expected results:
Ethereal discovers TTL set to 12 (per the hard coding in the application)

Additional info:
Could find nothing in bugzilla.  Not sure what module this belongs in.
Comment 1 Martin Bacovsky 2007-04-06 03:09:22 EDT
Changing component
Comment 2 Neil Horman 2007-06-04 16:29:30 EDT
Can you test on the lastest kernel update (4.5) and indicate if the problem
still occurs?  Thanks!
Comment 3 Philip N. Brazell 2007-06-04 16:57:48 EDT
Will do.
Comment 4 Neil Horman 2007-08-08 15:54:39 EDT
ping.  any update?
Comment 5 Neil Horman 2007-08-29 10:45:00 EDT
again, ping.  Any update?
Comment 6 Neil Horman 2007-12-10 11:07:06 EST
closing. no response

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