Re: [BEHAVE] Home NAPT44 - How many ports?

"Rajiv Asati (rajiva)" <rajiva@cisco.com> Wed, 05 June 2013 18:58 UTC

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From: "Rajiv Asati (rajiva)" <rajiva@cisco.com>
To: "Reinaldo Penno (repenno)" <repenno@cisco.com>, Michael Richardson <mcr+ietf@sandelman.ca>, "v6ops@ietf.org" <v6ops@ietf.org>
Thread-Topic: [BEHAVE] Home NAPT44 - How many ports?
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Date: Wed, 5 Jun 2013 18:57:05 +0000
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Cc: "Softwires-wg list \(softwires@ietf.org\)" <softwires@ietf.org>, "Poscic, Kristian \(Kristian\)" <kristian.poscic@alcatel-lucent.com>, "behave@ietf.org" <behave@ietf.org>, "Erik Kline \(ek@google.com\)" <ek@google.com>
Subject: Re: [BEHAVE] Home NAPT44 - How many ports?
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> >If one is doing CGN, wouldn't it be reasonable to point customers' at a
> >recursive DNS server with an interface inside the CGN?
> 
> Yes. That's what I suggest. But some people use, say, Google's
> DNS/OpenDns/etc and in some other cases the network is not setup
> correctly.

And in some cases, it is not possible depending on where the NAT function is placed and where the DNS server is placed. I recently ran into this in a large mobile network design. 

Nonetheless, it is desired, but it is not really a big deal, since UDP NAT usage tends to be a lot less than that TCP NAT usage (barring few exceptions).

> >This seems to also suggest that having a *caching* recursive DNS(SEC,
> >HOMENET+, mDNS+) server inside the customer router is also a big win.
> 
> Yes, it is.

Well, DNS resolver with or without proxy is a big win, I would say. 


Cheers,
Rajiv


> -----Original Message-----
> From: Reinaldo Penno (repenno)
> Sent: Wednesday, June 05, 2013 12:28 PM
> To: Michael Richardson; v6ops@ietf.org
> Cc: Poscic, Kristian (Kristian); Rajiv Asati (rajiva); Softwires-wg list
> (softwires@ietf.org); behave@ietf.org; Erik Kline (ek@google.com)
> Subject: Re: [BEHAVE] Home NAPT44 - How many ports?
> 
> 
> 
> On 6/5/13 1:23 PM, "Michael Richardson" <mcr+ietf@sandelman.ca> wrote:
> 
> >
> >>>>>> "repenno" == repenno  <Reinaldo> writes:
> >    repenno> On the other hand, as Rajiv captured,the number of
> >    repenno> UDP sessions can be much larger than the number of
> >    repenno> TCP. Because the way
> >    repenno> dynamic webpages are constructed today, there are
> sometimes
> >    repenno> literally 100s
> >    repenno> of DNS requests to download a single page.
> >
> >If one is doing CGN, wouldn't it be reasonable to point customers' at a
> >recursive DNS server with an interface inside the CGN?
> 
> Yes. That's what I suggest. But some people use, say, Google's
> DNS/OpenDns/etc and in some other cases the network is not setup
> correctly.
> 
> >
> >This seems to also suggest that having a *caching* recursive DNS(SEC,
> >HOMENET+, mDNS+) server inside the customer router is also a big win.
> 
> Yes, it is.
> 
> >
> >--
> >]               Never tell me the odds!                 | ipv6 mesh
> >networks [
> >]   Michael Richardson, Sandelman Software Works        | network
> >architect  [
> >]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails
> >   [
> >