similar to: SYN Attacks - how i cant stop it

Hi, This is the first time I've come across this: pid 11415 (ipfw), uid 0: exited on signal 11 (core dumped) The core dump landed in root's home directory in one of my jails. Has anyone seen this before? Should I be concerned? chkrootkit says nothing. (How trustworthy is its output? ;-) Thanks. Cheers. -- Ng Pheng Siong <ngps@netmemetic.com> http://firewall.rulemaker.net

Heya folks First of all, sorry if this isn't the correct list, but yet, I think spam is a kind of network attack and should be treated as a security issue.. I run a working mail server using Postfix, MySQL, Courier-IMAP, SpamAssassin and ClamAV (amavisd-new) .. I've checked the configuration file for SpamAssassin, but yet I havn't find any good solution for spam.. Sure, spam will

Hey Guys, today I upgraded to 4.8-RELEASE-p15. As usual I set IPFIREWALL to default accept in my kernel config file. Config & make weren't complaining so, installed the kernel, reboot and there it was: >IP packet filtering initialized, divert disabled, rule-based forwarding enabled, default to deny, logging disabled Another rebuild didn't work out so... I reviewed

Hello, I current have a FreeBSD 4.8 bridge firewall that sits between 7 servers and the internet. The servers are being attacked with syn floods and go down multiple times a day. The 7 servers belong to a client, who runs redhat. I am trying to find a way to do some kind of syn flood protection inside the firewall. Any suggestions would be greatly appreciated. -- Ryan James ryan@mac2.net

Hi, folks @ freebsd-security. First, I am not sure if this is apropriate topic for that list, so sorry, if it is not. Some time ago I have read rfc1948 (protection from blind TCP spoofing) and became interested in the way how it is implemented in FreeBSD. After some googling (BTW if you like Google you might be interested in this: http://register.spectator.ru/img/bart.gif ), I found this:

Heya, FREEBSD 4.9-STABLE Is there anyway to block SYN attacks and prevent it from bring down my server? Its been attacking for sometime.

Default,syncookies are activate when syn list(backlog queue) is full. I want hybrid system. I propose a system , syncookies active dynamic per connection . where will I write code , where syncookies system does call in the code file.

Hi, Two quick questions that I can't seem to find answers for using google. 1) is is possible to listen outside an ipfw firewall - that is have ethereal record the packets before ipfw starts dropping them? If so how? 2) Is there an api to ipfw that will let me manipulate rules, query stats etc? I need something faster than running the command line binary? Thanks John

First thing to note is that I am using FreeBSD 4.8 . We would like to send only the syn packet of a tcp connection through certain ipsec tunnels and the rest of the packets in a connection though a simple transport mode setup. Yeah, I know it's strange but what can I say -- we do a lot of strange things. From the best I can tell, the setkey/spadd filtering capability isn't sophisticated

This note is essentially a request for a reality check. I use IPFW & natd on the box that provides the interface between my home networks and the Internet; the connection is (static) residential DSL. I configured IPFW to accept & log all SSH "setup" requests, and use natd to forward such requests to an internal machine that only accepts public key authentication; that

Hi, First of all, I know that not dropping SYN/FIN isn't really a big deal, it just makes no sense. But since it doesn't make any sense, I don't see the reason why not to discard them. I'm running pf on FreeBSD 5.4-RELEASE-p3 and I scrub any traffic. I've read some other posts on google and as far as I can tell, clearly invalid packets (like packets with SYN/RST set) is

Hello Everyone, I have 2 different suggestions about syn-cookies method which is used to block syn-flood attacks. Syn cookies bitwise image --------------------------------------------- T(5 bits) ---MSS(3 bits)-----H(24 bits) --------------------------------------------- So, 1- T value can be decreased to 2 bit which is already 5 bit.And hash value will be 27 bit. 2-Normally syn-cookies is

-- On Friday, November 21, 2003 12:48 PM -0800 "David Wolfskill - david@catwhisker.org" <+freebsd-security+openmacnews+0459602105.david#catwhisker.org@spamgourmet.com> wrote: David, thanks for your reply! >> i've been struggling with setting appropriate rules for an SMTP-server >> behind by NAT'd firewall. > > OK.... <snip> > >>

In my recent security email, I got the following errors: cantona.dnswatchdog.com login failures: Aug 20 02:37:19 cantona sshd[9444]: fatal: Write failed: Operation not permitted Aug 20 04:30:42 cantona sshd[16142]: fatal: Write failed: Operation not permitted Aug 20 21:21:51 cantona sshd[45716]: fatal: Write failed: Operation not permitted So three questions: What is it? Should I be worried?

Hi ! First of all, I am sorry if this is not the list for that, but I've been learning (a little bit...) a way to implement a freeBSD firewall. So far I came up with a set of rules I would like to show you for commenting. I am sure there're a lot of errors and/or stupid rules (I am not sure the rules order is good for what I need) and I would be really pleased if one could have a look

Hi everyone, today I got an e-mail from a company claiming that my server is doing port scans on their firewall machine. I found that hard to believe so I started checking the box. The company rep told me that the scan was originating at port 80 with destination port 8254 on their machine. I couldn't find any hints as to why that computer was subject to the alleged port scans. Searching

Does anyone know of a way to rate limit ssh connections from an IP address ? We are starting to see more and more brute force attempts to guess simple passwords "/usr/sbin/inetd -wWl -C 10" is nice for slowing down attempts to services launched via inetd. Is there an equiv method for doing this to sshd? Running from inetd has some issues supposedly. ---Mike

Hi peeps, After compiling ipfw into the new 6.2 kernel, and typing "ipfw list", all I get is: "65535 deny ip from any to any" From reading the docs, this might indicate that this is the default rule. (I am certainly protected this way--but can't be very productive ;^) ) By the way, when I run "man ipfw" I get nothing. Using this instead:

Hi there, Is there some way to configure ipfw to do traffic normalizing ("scrubbing", as in ipf for OpenBSD)? Is there any tool to do it for FreeBSD firewalling? I've heard that ipf was ported on current, anything else? TIA, /Dorin. __________________________________ Do you Yahoo!? Yahoo! Mail SpamGuard - Read only the mail you want. http://antispam.yahoo.com/tools

Hi, I have a router running BGP and OSPF (bird) on FreeBSD. Are there any best practises one can take in order to protect the network from DDoS attacks. I know this isn't easy. But I would like to secure my network as much as possible. Even if I'am not able to prevent or block a ddos I would like to get some info (snmp trap parhaps) regarding the attack. Then I can contact my ISP or