Ugly issue with conntrack

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello everyone,

I have a extrange issue with a conntrack entry. There is a nat server
configure in this way

    DMZ  194.139.30.0/23  ---  194.139.30.16  nat 192.168.12.100 ---- 
192.168.12.0/24  private network

The nat machine does postrouting in all traffic from the private network
to DMZ, and there is no problem but in one server in the DMZ with
windows 2008 server the traffic doesn't return to the origin, I can see
the traffic with tcpdump like this

17:19:23.971978 IP (tos 0x0, ttl  64, id 0, offset 0, flags [DF], proto:
ICMP (1), length: 84) 192.168.12.91 > 194.139.30.62: ICMP echo request,
id 12075, seq 1, length 64    <-----   The echo request original OK

17:19:23.972094 IP (tos 0x0, ttl  63, id 0, offset 0, flags [DF], proto:
ICMP (1), length: 84) 194.139.30.16 > 194.139.30.62: ICMP echo request,
id 12075, seq 1, length 64    <------ Masquerade the source IP OK

17:19:23.972164 IP (tos 0x0, ttl 128, id 25050, offset 0, flags [none],
proto: ICMP (1), length: 84) 194.139.30.62 > 194.139.30.16: ICMP echo
reply, id 12075, seq 1, length 64    <------- The echo reply OK

¿?¿?¿?   <-----------    Lost echo reply not OK

There isn't the packet from 194.139.30.16 to 192.168.12.91 despite off
the conntrack table show

cat /proc/net/ip_conntrack | grep '30.62'
icmp     1 29 src=192.168.12.91 dst=194.139.30.62 type=8 code=0 id=12075
packets=11 bytes=924 [UNREPLIED] src=194.139.30.62 dst=194.139.30.16
type=0 code=0 id=12075 packets=0 bytes=0 mark=0 use=1

The packet in tcpdump match on the conntrack entry. "id 12075" in both
cases, but if I LOG the traffic with the LOG iptables target I see the
reply in INPUT table not in the FORWARD.

Thank you and sorry for me bad english.


--
To unsubscribe from this list: send the line "unsubscribe netfilter" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Index of Archives]     [Linux Netfilter Development]     [Linux Kernel Networking Development]     [Netem]     [Berkeley Packet Filter]     [Linux Kernel Development]     [Advanced Routing & Traffice Control]     [Bugtraq]

  Powered by Linux