On Feb 25, 2014, at 12:22 PM, Staudinger, Malcolm <mstaudinger@corp.earthlink.com> wrote:
Why wouldn't you just block chargen entirely? Is it actually still being used these days for anything legitimate?
More politely stated, it’s not the responsibility of the operator to decide what belongs on the network and what doesn’t. Users can run any services that’s not illegal or even reuse ports for other applications. That being said commonly exploited ports (TCP 25 for example) are often blocked. This is usually done to block or protect an application though not to single out a particular port number.
Malcolm Staudinger Information Security Analyst | EIS EarthLink
E: mstaudinger@corp.earthlink.com
-----Original Message----- From: Blake Hudson [mailto:blake@ispn.net] Sent: Tuesday, February 25, 2014 8:58 AM To: nanog@nanog.org Subject: Re: Filter NTP traffic by packet size?
I talked to one of our upstream IP transit providers and was able to negotiate individual policing levels on NTP, DNS, SNMP, and Chargen by UDP port within our aggregate policer. As mentioned, the legitimate traffic levels of these services are near 0. We gave each service many times the amount to satisfy subscribers, but not enough to overwhelm network links during an attack.
--Blake
Chris Laffin wrote the following on 2/23/2014 8:58 AM:
Ive talked to some major peering exchanges and they refuse to take any action. Possibly if the requests come from many peering participants it will be taken more seriously?
On Feb 22, 2014, at 19:23, "Peter Phaal" <peter.phaal@gmail.com> wrote:
Brocade demonstrated how peering exchanges can selectively filter large NTP reflection flows using the sFlow monitoring and hybrid port OpenFlow capabilities of their MLXe switches at last week's Network Field Day event.
http://blog.sflow.com/2014/02/nfd7-real-time-sdn-and-nfv-analytics_19 86.html
On Sat, Feb 22, 2014 at 4:43 PM, Chris Laffin <claffin@peer1.com> wrote: Has anyone talked about policing ntp everywhere. Normal traffic levels are extremely low but the ddos traffic is very high. It would be really cool if peering exchanges could police ntp on their connected members.
On Feb 22, 2014, at 8:05, "Paul Ferguson" <fergdawgster@mykolab.com> wrote:
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> On 2/22/2014 7:06 AM, Nick Hilliard wrote: > > On 22/02/2014 09:07, Cb B wrote: > Summary IETF response: The problem i described is already solved > by bcp38, nothing to see here, carry on with UDP udp is here to stay. Denying this is no more useful than trying to push the tide back with a teaspoon. Yes, udp is here to stay, and I quote Randy Bush on this, "I encourage my competitors to block udp." :-p
- - ferg
- -- Paul Ferguson VP Threat Intelligence, IID PGP Public Key ID: 0x54DC85B2
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