netfilter buglog - Mar 2003 - [Bug 70] New: udp connection(snmp) not being tracked.

https://bugzilla.netfilter.org/cgi-bin/bugzilla/show_bug.cgi?id=70

           Summary: udp connection(snmp) not being tracked.
           Product: netfilter/iptables
           Version: patch-o-matic
          Platform: All
        OS/Version: Debian GNU/Linux
            Status: NEW
          Severity: major
          Priority: P2
         Component: connection tracking
        AssignedTo: laforge@netfilter.org
        ReportedBy: difro@sexycoder.com
                CC: netfilter-buglog@lists.netfilter.org


Using kernel 2.4.20.
                                                                               
                                                                               
                               
I have a netfilter gateway with 2 external ip
eth0: 1.1.1.1 (gw: 1.1.1.254)
eth1: 2.2.2.2 (gw: 2.2.2.254)
                                                                               
                                                                               
                               
It has default route like this
                                                                               
                                                                               
                               
default
        nexthop via 1.1.1.254  dev eth0 weight 1
        nexthop via 2.2.2.254  dev eth1 weight 200
                                                                               
                                                                               
                               
SNMPd is running on the gateway (ucd-snmp).
                                                                               
                                                                               
                               
When I snmp-get to ip 1.1.1.1 (from outside the netfilter gateway, say
3.3.3.3), the reply comes back though eth1 with ip 2.2.2.2
                                                                               
                                                                               
                               
As you can see from what I captured of /proc/net/ip_conntrack, I think
udp packets are not being tracked properly.
(I've modified the ip address accordingly)
                                                                               
                                                                               
                               
-----------------
udp      17 29 src=2.2.2.2 dst=3.3.3.3 sport=161 dport=1914 [UNREPLIED]
src=3.3.3.3 dst=2.2.2.2 sport=1914 dport=161 use=1 mark=0
udp      17 28 src=2.2.2.2 dst=3.3.3.3 sport=161 dport=1913 [UNREPLIED]
src=3.3.3.3 dst=2.2.2.2 sport=1913 dport=161 use=1 mark=0
udp      17 27 src=2.2.2.2 dst=3.3.3.3 sport=161 dport=1912 [UNREPLIED]
src=3.3.3.3 dst=2.2.2.2 sport=1912 dport=161 use=1 mark=0
udp      17 27 src=3.3.3.3 dst=1.1.1.1 sport=1912 dport=161 [UNREPLIED]
src=1.1.1.1 dst=3.3.3.3 sport=161 dport=1912 use=1 mark=0
udp      17 28 src=3.3.3.3 dst=1.1.1.1 sport=1913 dport=161 [UNREPLIED]
src=1.1.1.1 dst=3.3.3.3 sport=161 dport=1913 use=1 mark=0
udp      17 29 src=3.3.3.3 dst=1.1.1.1 sport=1914 dport=161 [UNREPLIED]
src=1.1.1.1 dst=3.3.3.3 sport=161 dport=1914 use=1 mark=0
----------------
                                                                               
                                                                               
                               
I write a small UDP echo server/client and tested it on the gateway.
The result was same:  reply comes out from the wrong interface with
wrong ip.
                                                                               
                                                                               
                               
Is this a known bug?



------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.