Thank you, Comcast.
SNaslund at medline.com
Fri Feb 26 17:11:23 UTC 2016
Also worked fine in IE 11 and Firefox. I didn't change any particular security settings either. Might want to check your stuff before you rant on someone's web site.
From: NANOG [mailto:nanog-bounces at nanog.org] On Behalf Of Mike Hammett
Sent: Friday, February 26, 2016 10:01 AM
To: NANOG list
Subject: Re: Thank you, Comcast.
Works fine on a default Chrome installation. *shrugs*
Intelligent Computing Solutions
----- Original Message -----
From: "Keith Medcalf" <kmedcalf at dessus.com>
To: "NANOG list" <nanog at nanog.org>
Cc: "Nirmal Mody" <Nirmal_Mody at cable.comcast.com>
Sent: Friday, February 26, 2016 9:55:20 AM
Subject: RE: Thank you, Comcast.
On Friday, 26 February, 2016 08:13, Jason_Livingood at comcast.com said:
> FWIW, Comcast's list of blocked ports is at
> ports/. The suspensions this week are in direct response to reported
> abuse from amplification attacks, which we obviously take very seriously.
God is that a horrid web page. I cannot view it. The wheels on the bus go round and round non-stop.
I do not permit this. For anyone. Ever.
This pretty much ensures that I would never be one of your customers. If you cannot operate a server which serves renderable non-malicious web pages properly, what hope is there that you can do anything else right?
> We are in the process of considering adding some new ports to this
> block list right now, and one big suggestion is SSDP. If you have any
> others you wish to suggest please send them to me and the guy on the
> cc line (Nirmal Mody).
> On 2/26/16, 9:31 AM, "NANOG on behalf of Keith Medcalf" <nanog-
> bounces at nanog.org on behalf of kmedcalf at dessus.com> wrote:
> ISP's should block nothing, to or from the customer, unless they make
> it clear *before* selling the service (and include it in the Terms and
> Conditions of Service Contract), that they are not selling an Internet
> connection but are selling a partially functional Internet connection
> (or a limited Internet Service), and specifying exactly what the
> built-in deficiencies are.
> Deficiencies may include:
> port/protocol blockage toward the customer (destination blocks)
> port/protocol blockage toward the internet (source blocks) DNS
> diddling (filtering of responses, NXDOMAIN redirection/wildcards, etc)
> Traffic Shaping/Policing/Congestion policies, inbound and outbound
> Some ISPs are good at this and provide opt-in/out methods for at least
> the first three on the list. Others not so much.
> -----Original Message-----
> From: NANOG [mailto:nanog-bounces at nanog.org] On Behalf Of Maxwell Cole
> Sent: Friday, 26 February, 2016 07:19
> To: Mikael Abrahamsson
> Cc: NANOG list
> Subject: Re: Thank you, Comcast.
> I agree,
> At the very least things like SNMP/NTP should be blocked. I mean how
> many people actually run a legit NTP server out of their home?
> Dozens? And the
> people who run SNMP devices with the default/common communities aren't
> the ones using it.
> If the argument is that you need a Business class account to run a
> mail server then I have no problem extending that to DNS servers also.
> > On Feb 26, 2016, at 8:55 AM, Mikael Abrahamsson
> <swmike at swm.pp.se>
> > On Fri, 26 Feb 2016, Nick Hilliard wrote:
> >> Traffic from dns-spoofing attacks generally has src port =
> 53 and dst
> port = random. If you block packets with udp src port=53 towards
> customers, you will also block legitimate return traffic if the
> customers run their own DNS servers or use opendns / google dns / etc.
> > Sure, it's a very interesting discussion what ports should
> be blocked or
> > http://www.bitag.org/documents/Port-Blocking.pdf
> > This mentions on page 3.1, TCP(UDP)/25,135,139 and 445.
> They've been
> blocked for a very long time to fix some issues, even though there is
> legitimate use for these ports.
> > So if you're blocking these ports, it seems like a small
> step to block
> UDP/TCP/53 towards customers as well. I can't come up with an argument
> that makes sense to block TCP/25 and then not block port
> UDP/TCP/53 as
> well. If you're protecting the Internet from your customers
> misconfiguraiton by blocking port 25 and the MS ports, why not
> 53 as well?
> > This is a slippery slope of course, and judgement calls are
> not easy to
> > --
> > Mikael Abrahamsson email: swmike at swm.pp.se
More information about the NANOG