Howdy, >From my understanding, a message like "RES=0X00 ACK SYN URGP=0" would indicate a reply to a syn packet. Considering the source port is 22, I would suspect unauthorized access attempts on your server. On that note, I'd strongly advise, [if you've not already done so] that you use the PKI authentication mechanism and configure the SSH server to close any connection attempt to your server that fails to use this mechanism. Warm Regards Ukeme Noah -----Original Message----- From: netfilter-owner@xxxxxxxxxxxxxxx [mailto:netfilter-owner@xxxxxxxxxxxxxxx] On Behalf Of Velvet Pixel Sent: Friday, July 11, 2008 7:17 PM To: netfilter@xxxxxxxxxxxxxxx Subject: iptables help please Since upgrading my install from CentOS 5.1 to 5.2 and I am getting lots of errors in messages that look like they are iptables related. If anybody could help comment on my iptables rules to let me know if I have them set up incorrectly I would appreciate it :) This is on an OpenVZ VPS at a remote data center and not a box on my lan. Run chain banished Always Accept If input interface is lo Accept If protocol is TCP and TCP flags ACK (of ACK) are set Accept If state of connection is ESTABLISHED Accept If state of connection is RELATED Accept If protocol is TCP and source port is 53 Accept If protocol is UDP and source port is 53 Accept If protocol is ICMP and ICMP type is echo-reply Accept If protocol is ICMP and ICMP type is destination-unreachable Accept If protocol is ICMP and ICMP type is source-quench Accept If protocol is ICMP and ICMP type is time-exceeded Accept If protocol is ICMP and ICMP type is parameter-problem Accept If protocol is ICMP and ICMP type is echo-request Drop If protocol is TCP and destination port is ftp Accept If protocol is TCP and source is xx.xx.xx.xx and destination port is ssh Drop If protocol is TCP and destination port is ssh Accept If protocol is TCP and destination port is 25 Accept If protocol is TCP and destination port is 80 Accept If protocol is TCP and source is xx.xx.xx.xx and destination port is 110 Drop If protocol is TCP and destination port is 110 Accept If protocol is TCP and destination port is 113 Accept If protocol is TCP and source is xx.xx.xx.xx and destination port is 143 Drop If protocol is TCP and destination port is 143 Accept If protocol is TCP and destination port is 443 Drop If protocol is TCP and destination port is 465 Accept If protocol is TCP and source is xx.xx.xx.xx and destination port is 10000:10010 Drop If protocol is TCP and destination port is 10000:10010 Accept If protocol is TCP and source is xx.xx.xx.xx and destination port is 20000 Drop If protocol is TCP and destination port is 20000 Accept If source is 127.0.0.1 Accept If input interface is venet0 The xx.xx.xx.xx is my static IP for my home office. The chain banished is IPs of crackers that were repeatedly trying to get in my system and their source IPs are set to deny. The type of error I am seeing is: Jul 10 16:42:12 vps kernel: IN= OUT=venet0 SRC=IP.IP.IP.IP DST=zz.zz.zz.zz LEN=1452 TOS=0x08 PREC=0x00 TTL=64 ID=4361 DF PROTO=TCP SPT=22 DPT=63628 WINDOW=644 RES=0x00 ACK URGP=0 zz.zz.zz.zz=any ip accessing the server IP.IP.IP.IP=IP of the server My messages file is usually 44B and now in one day it is over 60MB!!! with thousands of those messages being logged so I need help :) Thanks, Cameron -- 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 -- 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
