Re: conntrackd failover works partially, was Re: conntrack performance test results in INVALID packets

[Bernhard Bock <mailinglists@bock.nu>]

Hi Pablo,

Pablo Neira Ayuso wrote:
> That's exactly the test that I do in my testbed and it works fine here,
> the problem must be elsewhere. The following line should help to see how
> the connection tracking is marking the traffic as invalid:
> 
> echo 255 > /proc/sys/net/ipv4/netfilter/ip_conntrack_log_invalid
> 
> However, please see the comment below before doing this and repeating
> the test.

I didn't know one can increase the verbosity. Now I get some (more)
helpful logs.

kernel: nf_ct_tcp: invalid packet ignored IN= OUT= SRC=10.5.0.101
DST=10.6.6.102 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=9977 DF PROTO=TCP
SPT=39101 DPT=80 SEQ=3381624888 ACK=0 WINDOW=5840 RES=0x00 SYN URGP=0 OPT

Invalid syn packet? Hm. And then:

kernel: nf_ct_tcp: killing out of sync session IN= OUT= SRC=10.6.6.102
DST=10.5.0.101 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=0 DF PROTO=TCP SPT=80
DPT=41647 SEQ=3243074286 ACK=3280173284 WINDOW=5792 RES=0x00 ACK SYN
URGP=0 OPT


> Are you using a sane stateful rule-set similar to the described in the
> conntrack-tools website? What kernel version are you using? If your
> kernel is < 2.6.22 you have to disabled TCP window tracking on both nodes.
> 
> echo 1 > /proc/sys/net/ipv4/netfilter/ip_conntrack_tcp_be_liberal


I'm using 2.6.25, from Fedora 9.
And I have set /proc/sys/net/netfilter/nf_conntrack_tcp_be_liberal to 1.

Here are my rules:

-A FORWARD -m state --state INVALID -j LOG --log-prefix "Invalid:"
-A FORWARD -m state --state INVALID -j DROP
-A FORWARD -p tcp ! --syn -m state --state NEW -j LOG --log-prefix "New
not syn:"
-A FORWARD -p tcp ! --syn -m state --state NEW -j DROP
-A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
-A FORWARD -m state --state NEW -m tcp -p tcp --syn -d 10.6.6.0/24 -j ACCEPT
-A FORWARD -m state --state NEW -m udp -p udp -s 10.5.0.0/24 -d
10.6.6.0/24 -j ACCEPT
-A FORWARD -j LOG --log-prefix "Packet dropped:"
-A FORWARD -j DROP


> There is a new script `primary-backup.sh' that replaces the old
> script_master.sh and script_backup.sh. Although this is not directly
> related it would be worth to use that instead as it will be the standard
> in the upcoming release.

I'll replace it for future tests. For now, I don't want to mess around
at too many places at the same time unless it's related to the problem.

best regards
Bernhard