similar to: Re: Expected handling of [SYN] when expecting[SYN, ACK]?

Hi, I''ve been developing a peer-to-peer application, and have recently been trying to add STUNT (http://www.cis.nctu.edu.tw/~gis87577/xDreaming/XSTUNT/Docs/XSTUNT%20Ref erence.htm) to allow firewall/NAT traversal. I got a box with Shorewall to use for testing, and am now trying to work out whether Shorewall is actually designed to prevent such connections? I notice in the FAQs that

I have, for the time being, decided to split my dual ISP/single shorewall connection into two shorewall connections/boxes, each handling one ISP. I am running OSPF in the network and so far things are working out fairly well (from a client of the two gateways). $ ip route ls 10.33.66.2 via 10.75.22.199 dev eth0 proto zebra metric 20 192.168.200.1 via 10.75.22.254 dev eth0 proto zebra metric

I have found a very strange problem. We found that the time of establishing the websocket connection between mobile phone and server was too long. Then I use tcpdump to capture the data and found that the problem maybe has something to do with window scale option in SYN packet. Here is the SYN packet for websocket connection: 55488 ? 443 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 WS=64

This release back-ports the DROPINVALID shorewall.conf option from 2.2.0. 1) Recent 2.6 kernels include code that evaluates TCP packets based on TCP Window analysis. This can cause packets that were previously classified as NEW or ESTABLISHED to be classified as INVALID. The new kernel code can be disabled by including this command in your /etc/shorewall/init file: echo 1

Hi, i have a problem concerning my previous shorewall installation. I tried to use shorewall to configure my firewall, but i couldn''t get NAT to work. So i decided to remove shorewall and tried it with plain iptables. This is now working for me but everytime when i start my network connection it seems that my handmade iptable rules are overwritten. I have to manually run my

Hello All I installed shorewall 3.0.8 on Centos 4.3 with openvz.org kernel it work well i have in this Host 3 virtual servers (VPS) i can access from a VPS to the internet , and with NAt rule (Via Shorewall) i can access from Internet to the 3 VPS. i want that all the 3 VPS can communicate between them. i can''t do a tcp connection from a VPS to an other , in my shorewall log in the

I have a question about tcp layer of linux kernel. I want, Syn and ack packages received to server will be counted. [image: enter image description here] where total_syn_count and total_ack_count are variables to be defined and will be increased Which files to be used ???? tcp_input.c ,tcp_output.c , tcp_ipv4.c

http://shorewall.net/pub/shorewall/2.2-Beta/shorewall-2.2.0-Beta8 ftp://shorewall.net/pub/shorewall/2.2-Beta/shorewall-2.2.0-Beta8 Problems Corrected: 1. A typo in the /etc/shorewall/interfaces file has been corrected. 2. Previously, the "add" and "delete" commands were generating incorrect policy matches when policy match support was available. New

Hi, I''m interested in prioritizing all packets with the SYN bit on, both with and without the ACK bit on (but specially the SYN ACKS). I am checking is the use of Diffserv. From a paper I read I understood that when Diffserv is on, all "Control Traffic", including TCP SYN-ACKs, gets by default into "band 0" of Diffserv, the highest priority out of 16 bands. If true,

Hi *Problem *- I'm running Icecast in a VM container on OpenVZ. Syslog on the hardware node (HN) shows these error messages: Jan 23 18:43:05 HN kernel: [27469893.430615] possible SYN flooding on port 8000. Sending cookies. Jan 23 21:37:40 HN kernel: [27480362.817944] possible SYN flooding on port 8000. Sending cookies. Jan 23 23:43:50 HN kernel: [27487929.582025] possible SYN flooding on

Hi, sorry to bother you, and that this is probably not the right list :-), but I read that some of you might use syn as Editor for .R files. I've released an unofficial Version of the syn Text Editor with improved support for R (I'm the initial developer of this program, btw.). syn is a Windows 32 Program (Win9x, NT4, 2000), but maybe it runs also inside Wine, I didn't try it.

Perhaps someone will help me on this :- I have read a lot of examples of syn flood protect on the INPUT chain. That I have no question at all. I wonder if it make sense to perform syn flood protection at the FORWARD chain ? If packets are originated from a LAN worm, and are not targetted at the firewall itself, but rather at hosts in the internet, will it cause problem with the firewall itself,

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have a situation where some Poptop/PPTP sessions (only with FC5/Shorewall to FC5/Shorewall firewall in between) cause the following to appear in the state table (shorewall show connections). unknown 47 420 src=XX.234.79.183 dst=XX.234.137.226 packets=2 bytes=130 [UNREPLIED] src=XX.234.137.226 dst=XX.234.79.183 packets=0 bytes=0 mark=0 use=1

I have just finished a patch to linux 2.0.29 that provides the SYN cookies protection against SYN flood attacks. You can grab it from my home page at: http://www.dna.lth.se/~erics/software/tcp-syncookies-patch-1.gz You can also follow the pointers from my home page (see the signature) to get a very short blurb about this patch. Quick synopsys: This implements the SYN cookie defense against SYN

On 07/20/2018 03:56 AM, Leon Fauster via CentOS wrote: > Hi folks, > > I have here a database node running > > # rpm -qa | grep mysql-server > mysql55-mysql-server-5.5.52-1.el6.x86_64 > > on > > # virt-what > vmware > > > that seems to have a connection problem: > > # dmesg |grep SYN |tail -5 > possible SYN flooding on port 3306. Sending cookies.

Hi everyone, I see that shorewall has "ratelimit" but i''m interested in deny conexions by number of them, not by number/sec. Is connlimit feature supported by shorewall? Or maybe someone have an extraofficial patch for them? Regards, Angel Mieres ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT

On a Linux Server running tincd I noticed the following log message in /var/log/messages kernel: possible SYN flooding on port 655. Sending cookies. I found this on the web: If SYN cookies are enabled, then the kernel doesn't track half open connections at all. Instead it knows from the sequence number in the following ACK datagram that the ACK very probably follows a SYN and a SYN-ACK.

Hello, I changed the log path in shorewall.conf, LOGFILE=/var/log/messages to LOGFILE=/var/log/shorewall, and then I touched the shorewall file in /var/log, permission root:root 600, after shorewall restart, no logging messages appear in /var/log/shorewall. so how can I fix this problem ? Thanks !! _______________________________________ YM - 離線訊息

Hi folks, I have here a database node running # rpm -qa | grep mysql-server mysql55-mysql-server-5.5.52-1.el6.x86_64 on # virt-what vmware that seems to have a connection problem: # dmesg |grep SYN |tail -5 possible SYN flooding on port 3306. Sending cookies. possible SYN flooding on port 3306. Sending cookies. possible SYN flooding on port 3306. Sending cookies. possible SYN flooding on

Hello All, is it good to DROP all packets coming from net to other zones, like dmz, loc & fw? or should I REJECT Here is my Policy for packets from net: net $FW DROP info net loc DROP info net dmz DROP info net all DROP info all all