New: when a system is configured as a bridge, and at the same time configured to have multipath weighted route, with one leg goes thru NAT and another without NAT, the nat path will intermittently get packets leaking out using internal IP without being SNAT-ted
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A message that is not in the archive (sent off-list or not yet received): [email protected]/
(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).
Quoted 21 lines · On Wed, 9 Jan 2008 11:55:50 -0800 (PST) [email protected] wrote:
http://bugzilla.kernel.org/show_bug.cgi?id=9719
Summary: when a system is configured as a bridge, and at the same
time configured to have multipath weighted route, with one leg goes thru NAT and another without NAT, the nat path will intermittently get packets leaking out using internal IP without being SNAT-ted
Product: Networking
Version: 2.5
KernelVersion: 2.6.22.15 and 2.6.23
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Netfilter/Iptables
AssignedTo: [email protected]
ReportedBy: [email protected]
Quoted 2 lines
Latest working kernel version: 2.6.23
Earliest failing kernel version: 2.6.22.15
This doesn't make sense. What we're trying to ask here (and we've been unable to find a pair of questions which 100% of reporters can successfully answer) is whether this is a regression, and in which kernel release did we regress?
In other words: did we break it, and if so, when did we break it?
Quoted 36 lines
Distribution: iptables 1.4.0 was used with kernel 2.6.23 and iptables 1.3.8 with 2.6.22.15
Hardware Environment: 3 interfaces, 2 interfaces bridged to form br0, and another connects to internet using pppoe.
Software Environment: bridge, multipath routing
Problem Description: when a system is configured as a bridge with IP assigned to br0 interface, and at the same time it is configured to have multipath weighted default route, and one of the default route is NAT-ed and another of the default route is not NAT-ed, then it is NAT-ed interface will occasionally get packets leaking out to it with packets with private IPs.Steps to reproduce:
1) setup the bridge interface and assign an IP to it
2) setup an default gateway on side B of the bridge ( without NAT ) and default route the bridge to this gateway.
3) Setup a client on side A of the bridge and default route to the bridge br0 interface.
4) Start ping'ing an internet site, for example www.google.com from the client. Run the ping continuously, for example :-
while true
do
ping -c 1 www.google.com
sleep 1
done
5) after successfully and consistently getting a ping response from the www.google.com, on the bridge system start up another uplink to the internet, but this uplink is SNAT-ed( eg iptables -t nat -A POSTROUTING -o eth2 -j MASQUERADE )
6) verify and make sure that the second uplink is working.
7) change the default route on the bridge to multipath weighted route with equal weight on both the uplinks.
8) sniff the NAT-ed inteface for packets coming in from the LAN client. Occasionallly packets with private IP leaks to the NAT-ed interface.
Quoted 32 lines · Andrew Morton
(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).
Quoted 21 lines · On Wed, 9 Jan 2008 11:55:50 -0800 (PST) [email protected] wrote:
http://bugzilla.kernel.org/show_bug.cgi?id=9719
Summary: when a system is configured as a bridge, and at the same
time configured to have multipath weighted route, with one leg goes thru NAT and another without NAT, the nat path will intermittently get packets leaking out using internal IP without being SNAT-ted
Product: Networking
Version: 2.5
KernelVersion: 2.6.22.15 and 2.6.23
Platform: All
OS/Version: Linux
Tree: Mainline
Status: NEW
Severity: normal
Priority: P1
Component: Netfilter/Iptables
AssignedTo: [email protected]
ReportedBy: [email protected]Quoted 3 lines
Latest working kernel version: 2.6.23
Earliest failing kernel version: 2.6.22.15
Quoted 7 lines
This doesn't make sense. What we're trying to ask here (and we've been unable to find a pair of questions which 100% of reporters can successfully answer) is whether this is a regression, and in which kernel release did we regress?
In other words: did we break it, and if so, when did we break it?
Sorry for the confusion and for such a lousy first time bug reporter.
I realized that mistake immediately after I posted it on the web interface. However, the web interface does not seem to allow me to correct that.
What I meant was that it failed on both the kernel versions I tested. I am afraid it is a problem which exists all a long. Perhaps it has been broken quite sometime already. I need to go back to try some older kernel version and see if I could repeat the problem.
Regards.
Quoted 2 lines · Ming-Ching Tiew
What I meant was that it failed on both the kernel versions I tested. I am afraid it is a problem which exists all a long. Perhaps it has been broken quite sometime already. I need to go back to try some older kernel version and see if I could repeat the problem.
OK based on the I repeat the problem, so far I could not find such misbehaviour on kernel 2.6.18. I will do more tests to make it more conclusive.
Quoted 6 lines · Ming-Ching Tiew
Quoted 2 lines · Ming-Ching Tiew
What I meant was that it failed on both the kernel versions I tested. I am afraid it is a problem which exists all a long. Perhaps it has been broken quite sometime already. I need to go back to try some older kernel version and see if I could repeat the problem.
OK based on the I repeat the problem, so far I could not find such misbehaviour on kernel 2.6.18. I will do more tests to make it more conclusive.
Sorry for jumping the gun. Kernel 2.6.18 has the same problem too. I think from now on, I will refrain from early posting until conclusive results.
Quoted 10 lines · Andrew Morton
Quoted 10 lines
Distribution: iptables 1.4.0 was used with kernel 2.6.23 and iptables 1.3.8 with 2.6.22.15
Hardware Environment: 3 interfaces, 2 interfaces bridged to form br0, and another connects to internet using pppoe.
Software Environment: bridge, multipath routing
Problem Description: when a system is configured as a bridge with IP assigned to br0 interface, and at the same time it is configured to have multipath weighted default route, and one of the default route is NAT-ed and another of the default route is not NAT-ed, then it is NAT-ed interface will occasionally get packets leaking out to it with packets with private IPs.
That is most likely because the route changes over time (when the cache is flushed) and the NAT mappings for the connection have been set up on a different interface. The way to properly do this is to add routing rules based on fwmark and use CONNMARK to bind a connection to one of the interfaces after the initial multipath routing decision.
Quoted 13 lines · Patrick McHardy
Quoted 10 lines · Andrew Morton
Quoted 10 lines
Distribution: iptables 1.4.0 was used with kernel 2.6.23 and iptables 1.3.8 with 2.6.22.15
Hardware Environment: 3 interfaces, 2 interfaces bridged to form br0, and another connects to internet using pppoe.
Software Environment: bridge, multipath routing
Problem Description: when a system is configured as a bridge with IP assigned to br0 interface, and at the same time it is configured to have multipath weighted default route, and one of the default route is NAT-ed and another of the default route is not NAT-ed, then it is NAT-ed interface will occasionally get packets leaking out to it with packets with private IPs.
Quoted 6 lines
That is most likely because the route changes over time (when the cache is flushed) and the NAT mappings for the connection have been set up on a different interface. The way to properly do this is to add routing rules based on fwmark and use CONNMARK to bind a connection to one of the interfaces after the initial multipath routing decision.
First of all, I would like to say a big thank you to all of you takes interest in replying my post/email. I have altered the distribution slightly and the kernel bug list is removed.
It seems from your reply, what is implied is that I cannot change route within a connection, and whatever things I do, I must make sure that the route remains the same for a particular netfilter connection ?
Regards.