Requirements for IPv6 Firewalls

Christopher Morrow morrowc.lists at
Tue Apr 22 19:45:57 UTC 2014

On Tue, Apr 22, 2014 at 3:41 PM, Matthew Huff <Matthew.Huff at> wrote:
> I think some of the disconnect is the difference between a provider network and a corporate one.
> For example, if it is highly visible and has a high traffic rate would have  load balancers and line rate routers, but no statefull firewalls.
> Corporate, on the other hand, where end-users, and internal servers reside, almost certainly has a statefull firewall.

doesn't this come down to design of the whole system though?

or rather, I bet roland would point out that this comes down to the
design of the whole system... and tradeoffs folk decide to make/break.

watching a corporate mail server complex melt down because some 'well
intentioned admin' put a stateful firewall (with a single rule;
"permit smtp"!) in front of the mail servers ... Having to explain to
them (and losing because 'policy') that 'permit tcp any any eq 25' was
more effective and better for their systems health was quite painful.

eventually the CIO didn't listen and he works elsewhere.

> Personally, if I were told to use only host based security on a corporate network and no central administrated firewall, I'd be shopping my resume.

why? sure there's a place for things like firewalls, but there's also
a fine place for just 'drop packets with filters and don't maintain
state'.  it really comes down to the design goals of the whole system.


> ----
> Matthew Huff             | 1 Manhattanville Rd
> Director of Operations   | Purchase, NY 10577
> OTA Management LLC       | Phone: 914-460-4039
> -----Original Message-----
> From: Christopher Morrow [mailto:morrowc.lists at]
> Sent: Tuesday, April 22, 2014 3:18 PM
> To: Brian Johnson
> Cc: nanog at
> Subject: Re: Requirements for IPv6 Firewalls
> On Tue, Apr 22, 2014 at 2:55 PM, Brian Johnson <bjohnson at> wrote:
>> Eric,
>> If you read what he posted and really believe that is what he is saying, you need to re-think your career decision. It is obvious that he is not saying that.
> Roland's saying basically:
>   1) if you deploy something on 'the internet' you should secure that something
>   2) the securing of that 'thing' should NOT be be placing a stateful device between your users and the 'thing'.
> In a simple case of:
>   "Put a web server on the internet"
> Roland's advice breaks down to:
>   1) deploy server
>   2) put acl on upstream router like:
>       permit tcp any any eq 80
>       deny ip any any
>   3) profit
> The router + acl will process line-rate traffic without care.
> -chris
>> I hate it when threads breakdown to this type of tripe and ridiculous restatement of untruths.
>> - Brian
>>> -----Original Message-----
>>> From: Eric Wieling [mailto:EWieling at]
>>> Sent: Tuesday, April 22, 2014 1:16 PM
>>> To: Dobbins, Roland; nanog at
>>> Subject: RE: Requirements for IPv6 Firewalls
>>> It seems to me you are saying we should get rid of firewalls and rely
>>> on applications network security.
>>> This is so utterly idiotic I must be misunderstanding something.    There are a
>>> few things we can count on in life, death, taxes, and application
>>> developers leaving giant security holes in their applications.
>>> -----Original Message-----
>>> From: Dobbins, Roland [mailto:rdobbins at]
>>> Sent: Saturday, April 19, 2014 12:10 AM
>>> To: nanog at
>>> Subject: Re: Requirements for IPv6 Firewalls
>>> You can 'call' it all you like - but people who actually want to keep
>>> their servers up and running don't put stateful firewalls in front of
>>> them, because it's very easy to knock them over due to state
>>> exhaustion.  In fact, it's far easier to knock them over than to knock over properly-tuned naked hosts.
>>> Also, you might want to search the NANOG email archive on this topic.
>>> There's lots of previous discussion, which boils down to the fact
>>> that serious organizations running serious applications/services
>>> don't put stateful firewalls (or 'IPS', or NATs, et. al.) in front of their servers.
>>> The only way to secure hosts/applications/service against compromise
>>> is via those hosts/applications/services themselves.  Inserting
>>> stateful middleboxes doesn't actually accomplish anything to enhance
>>> confidentiality and integrity, actually increases the attack surface
>>> due to middlebox exploits (read the numerous security notices for
>>> various commercial and open-source stateful firewalls for compromise
>>> exploits), and has a negative impact on availability.

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