Date: Sun, 10 Feb 2013 10:06:07 +0100 From: James Howlett <jim.howlett@outlook.com> To: "khatfield@socllc.net" <khatfield@socllc.net> Cc: "freebsd-isp@freebsd.org" <freebsd-isp@freebsd.org>, "freebsd-security@freebsd.org" <freebsd-security@freebsd.org> Subject: RE: FreeBSD DDoS protection Message-ID: <SNT002-W126C067EAA248C592EBB424E50B0@phx.gbl> In-Reply-To: <321927899.767139.1360461430134@89b1b4b66ec741cb85480c78b68b8dce.nuevasync.com> References: <SNT002-W152BF18F12BD59F112A1CBAE5040@phx.gbl>, <321927899.767139.1360461430134@89b1b4b66ec741cb85480c78b68b8dce.nuevasync.com>
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Hello,
Kevin, thank You for the information.
> FreeBSD is fairly simple to harden against smaller DDoS attacks. Since I am unsure of your connection I cannot recommend specifics. However, it is best to configure polling, tweak sysctl (buffers/sockets/etc), install pf or ipfw and do some straight forward deny/allow + source spoof settings.
>
> Above all, don't go overboard with firewall configuration. People often try to do far too much tracking/packet rate limiting, etc. It just burns up free resources.
>
Let me tell You a bit about my setup. All my connections to ISP's are 1Gigabit each.
They are terminated on a my switch, and the router is connected to that switch.
> Deny all ICMP (drop I mean) and UDP except where specifically required.
Is droping ICMP really helpful? I can limit ICMP only to my monitoring host - that is no problem.
> And just do general hardening... Get yourself a static IP or VPN. Deny all console/ssh access except to that IP. Same here, a simple host deny will satisfy this need.
>
This is already done. I also have out of band management to my router over a different network connection. If all my ISP's fail I can still connect to that router.
> The less you do with the firewall (routing/blocking/inspecting) the better.
>
> Drop drop drop ;)
>
> In the end, proper tuning with a good Intel NIC and you can saturate a 1Gbps connection with legit traffic and block most high PPS floods as long as they don't saturate the link.
>
I have the following ethernet cards in my router:
device = '82579LM Gigabit Network Connection'
device = '82571EB Gigabit Ethernet Controller'
device = '82571EB Gigabit Ethernet Controller'
device = '82574L Gigabit Network Connection'
but at this moment I use only the 82571EB model.
> I have ran similar configurations in 10Gbps scenarios and there are certainly limitations even in 1Gbps cases... Though, you can't plan for everything - the best you can do is be prepared for the majority of general UDP/ICMP/TCP SYN or service specific attacks like SSH/FTP, etc.
>
At this moment an attack on 80 port kills my network connection with the number of PPS. 200000 is reached in a second and the router can't proccess any new connections.
> I'm actually at dinner so I apologize for the lack of further detail. I'm not even certain this makes sense but hopefully it helps.
>
There is nothing to apologize for - You are most helpful.
> I have my configs which I can send by tomorrow if needed. (For examples)
>
That would be great.
All best,
Jim
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