0.90.[01] packets match rules changed??

Graham Murray graham@barnowl.demon.co.uk
17 Feb 2000 21:38:50 +0000


Should iptables rules which worked with 0.1.18 still work in 0.90.x
without change? Mine do not seem to work.

Here is the output from iptable -L -v taken while running 0.90.1

Chain INPUT (policy DROP 12 packets, 528 bytes)
 pkts bytes target     prot opt in     out     source               destination         
   25  4262 ppp        all  --  ppp+   any     anywhere             anywhere           
    0     0 ACCEPT     udp  --  lo     any     anywhere             anywhere           udp dpt:domain 
    0     0 ACCEPT     tcp  --  lo     any     anywhere             anywhere           tcp dpt:domain 
   26  3299 ACCEPT     all  --  lo     any     anywhere             anywhere           

Chain FORWARD (policy DROP 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 51 packets, 4911 bytes)
 pkts bytes target     prot opt in     out     source               destination         

Chain ppp (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 LOG        all  --  any    any     anywhere            !barnowl.demon.co.ukLOG level alert prefix `bad_dest' 
    0     0 DROP       all  --  any    any     anywhere            !barnowl.demon.co.uk
    0     0 ACCEPT     tcp  --  any    any     anywhere             anywhere           tcp dpt:ssh Flags:SYN/SYN,RST,ACK
    0     0 tcp-fin    tcp  --  any    any     anywhere             anywhere           tcp Flags:FIN,ACK/FIN,SYN,RST,PSH,ACK,URG
    0     0 LOG        tcp  --  any    any    !194.217.242.0/24     anywhere           tcp dpt:smtp Flags:SYN/SYN,RST,ACKLOG level warning prefix `alien_smtp' 
    0     0 ACCEPT     tcp  --  any    any     anywhere             anywhere           tcp dpt:smtp Flags:SYN/SYN,RST,ACK
    0     0 ACCEPT     tcp  --  any    any     anywhere             anywhere           tcp dpt:auth Flags:SYN/SYN,RST,ACK
    0     0 ACCEPT     tcp  --  any    any     anywhere             anywhere           tcp dpt:finger Flags:SYN/SYN,RST,ACK
    0     0 ACCEPT     tcp  --  any    any     anywhere             anywhere           tcp dpt:ssl Flags:SYN/SYN,RST,ACK
    0     0 DROP       tcp  --  any    any     anywhere             anywhere           tcp spt:domain dpt:domain 
    0     0            tcp  --  any    any     anywhere             anywhere           tcp spt:domain 
    0     0 LOG        tcp  --  any    any     anywhere             anywhere           tcp dpt:1080 Flags:SYN/SYN,RST,ACKLOG level warning 
    0     0 DROP       tcp  --  any    any     anywhere             anywhere           tcp dpt:1080 Flags:SYN/SYN,RST,ACK
    0     0 LOG        tcp  --  any    any     anywhere             anywhere           tcp dpt:8080 Flags:SYN/SYN,RST,ACKLOG level notice 
    0     0 DROP       tcp  --  any    any     anywhere             anywhere           tcp dpt:8080 Flags:SYN/SYN,RST,ACK
    0     0 LOG        tcp  --  any    any     anywhere             anywhere           tcp dpts:0:1024 Flags:SYN/SYN,RST,ACKLOG level warning 
    0     0 DROP       tcp  --  any    any     anywhere             anywhere           tcp dpts:0:1024 Flags:SYN/SYN,RST,ACK
    0     0 LOG        tcp  --  any    any     anywhere             anywhere           tcp dpts:6000:6010 LOG level alert 
    0     0 DROP       tcp  --  any    any     anywhere             anywhere           tcp dpts:6000:6010 
    0     0 LOG        tcp  --  any    any     anywhere             anywhere           state INVALIDLOG level warning prefix `inv_conn' 
   12   528 LOG        tcp  --  any    any     anywhere             anywhere           state NEWLOG level warning prefix `new_conn' 
    5  2319 ACCEPT     tcp  --  any    any     anywhere             anywhere           state RELATED,ESTABLISHED
    0     0 ACCEPT     udp  --  any    any     anywhere             anywhere           udp dpt:domain 
    8  1415 ACCEPT     udp  --  any    any     anywhere             anywhere           udp spt:domain 
    0     0 ACCEPT     udp  --  any    any     anywhere             anywhere           udp spt:4000 
    0     0 ACCEPT     udp  --  any    any     anywhere             anywhere           udp spt:time 
    0     0 LOG        udp  --  any    any     anywhere             anywhere           udp dpt:netbios-ns LOG level notice 
    0     0 DROP       udp  --  any    any     anywhere             anywhere           
    0     0 DROP       icmp --  any    any     anywhere             anywhere           icmp redirect 
    0     0 ACCEPT     icmp --  any    any     anywhere             anywhere           

Chain tcp-fin (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 DROP       all  --  any    any     anywhere             anywhere           state INVALID,NEW,RELATED


You will notice that 12 packets are caught by the rule which generates
a 'new_conn' log entry. The following entry from my syslog shows one
of these, together with the trace information printed by iptables just
before the log entry. This packet should have been caught by the rule
" 0 0 ACCEPT tcp -- any any anywhere anywhere tcp dpt:smtp
Flags:SYN/SYN,RST,ACK" but was not. Under 0.1.xx (xx<=18) smtp
incoming connections are correctly caught by this rule.

Feb 17 21:18:51 barnowl kernel: SRC: 194.217.242.36. Mask: 0.0.0.0. Target: 0.0.0.0.
Feb 17 21:18:51 barnowl kernel: DST: 158.152.23.247 Mask: 255.255.255.255 Target: 158152.23.247. (INV)
Feb 17 21:18:51 barnowl kernel: Source or dest mismatch.
Feb 17 21:18:51 barnowl kernel: SRC: 194.217.242.36. Mask: 0.0.0.0. Target: 0.0.0.0.
Feb 17 21:18:51 barnowl kernel: DST: 158.152.23.247 Mask: 255.255.255.255 Target: 158152.23.247. (INV)
Feb 17 21:18:51 barnowl kernel: Source or dest mismatch.
Feb 17 21:18:51 barnowl kernel: SRC: 194.217.242.36. Mask: 255.255.255.0. Target: 194.217.242.0. (INV)
Feb 17 21:18:51 barnowl kernel: DST: 158.152.23.247 Mask: 0.0.0.0 Target: 00.0.0.
Feb 17 21:18:51 barnowl kernel: new_connIN=ppp0 OUT= MAC=45:00:00:2c SRC=194.217.242.36 DST=158.152.23.247 LEN=44 TOS=0x00 PREC=0x00 TTL=67 ID=51277 DF PROTO=TCP SPT=44540 DPT=25 WINDOW=8760 RES=0x00 SYN URGP=0