Another aspect, for those users that need to go the PSN network but experience 
issues via the CGNAT, an opt-out solution (giving them public IPv4) may should 
mitigate the problem, that PSN network does not support IPv6.

After all what percentage of your total subscribers that uses PSN and are 
gamers 2-3%  ?  Which might be relatively small amount to give public IPv4.


-----Original Message-----
From: NANOG [] On Behalf Of Roland Dobbins
Sent: Friday, September 16, 2016 4:32 PM
Subject: Re: PlayStationNetwork blocking of CGNAT public addresses

On 16 Sep 2016, at 20:12, Simon Lockhart wrote:

> Has anyone else come up against the problem, and/or have any 
> suggestions on how best to resolve it?

I'm pretty sure that at least part of it has to do with DDoS-related activity.  
The best bet is to try and identify and engage with the relevant operational 
personnel with clue.  Going the customer-service route isn't fruitful, as you 

Another aspect is ensuring that one has the ability to detect, classify, 
traceback, and mitigate outbound badness southbound of the CGN.

This sort of thing has always been a problem with NAT; as CGN becomes more 
prevalent on wireline broadband networks, it's only going to get worse.

AFAIK, PSN doesn't support IPv6.  That would be another topic of discussion 
with the operational folks.

Roland Dobbins <>

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