[CentOS] CentOS 5.2 + iptables + memcached Problem

Art Age Software artagesw at gmail.com
Fri Dec 12 20:45:49 UTC 2008


Hi,

I'm experiencing the most perplexing problem with iptables on CentOS
5.2. I'm hoping someone can point out what I must be missing here.

I have memcached set up on several nodes on an internal network. I
have the following rules set up to allow traffic between memcached
nodes:

IPTABLES -A INPUT  -i bond0 -p tcp -m tcp  -s 192.168.1.0/24  -d
192.168.1.0/24  --dport 11211  -j ACCEPT
IPTABLES -A FORWARD  -i bond0 -p tcp -m tcp  -s 192.168.1.0/24  -d
192.168.1.0/24  --dport 11211  -j ACCEPT
IPTABLES -A OUTPUT  -o bond0 -p tcp -m tcp  -s 192.168.1.0/24  -d
192.168.1.0/24  --dport 11211  -j ACCEPT
IPTABLES -A FORWARD  -o bond0 -p tcp -m tcp  -s 192.168.1.0/24  -d
192.168.1.0/24  --dport 11211  -j ACCEPT

And yet, iptables continues to drop memcached packets. It appears to
simply skip these rules and fall through to the default CATCH-ALL
policy. Here are some iptables log messages notifying of the dropped
packets:

Dec 12 20:33:53 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.2 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=47567 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:33:59 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.2 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=47771 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:34:00 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.2 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=35600 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:34:12 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.4 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=52823 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:34:40 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.4 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=44946 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:34:42 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.3 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=45046 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:37:40 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.4 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=58825 WINDOW=0 RES=0x00 RST URGP=0
Dec 12 20:37:49 s1 kernel: DROP -- Catch All: IN= OUT=bond0
SRC=192.168.1.1 DST=192.168.1.2 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=0
DF PROTO=TCP SPT=11211 DPT=44183 WINDOW=0 RES=0x00 RST URGP=0

I am not seeing anything like this with any of the other filtered
ports in my ruleset. Is there something obvious here that I am just
missing? Or am I running into a possible kernel bug of some sort?

Thanks in advance for any insights.


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