On Apr 20, 2011, at 1:40 PM, Joe Touch wrote:

> 
> 
> On 4/11/2011 12:49 PM, Stephen Kent wrote:
>> At 9:30 PM -0700 4/6/11, Brian Weis wrote:
>>> On Apr 6, 2011, at 5:46 PM, Randy Bush wrote:
>>> 
>>>>> Getting a new application (such as the rtr protocol) specifying
>>>>> hmac-md5 mandatory to implement through a Secdir review and then the
>>>>> Security ADs just won't happen. The only exception I can think of is
>>>>> if there were no possible alternatives, and that's obviously not the
>>>>> case here.
>>>> 
>>>> with AO not implemented on any servers, routers not having ssh
>>>> libraries, and this being a server to router protocol, what are the
>>>> alternatives?
>>>> 
>>>> randy
>>> 
>>> I'm surprised IPsec hasn't been mentioned in this thread ... was it
>>> previously discussed and rejected? Correct me if I'm wrong, but I
>>> believe it's common for BGP routers to support IPsec and servers
>>> definitely support IPsec. On the router side, one or two IPsec
>>> sessions to servers should not be a burden. I'm less sure of the
>>> server IPsec scaling properties, but I would expect a LINUX or BSD
>>> kernel to have the scaling issues as were discussed earlier in this
>>> thread regarding SSH but I'm no expert here.
>>> 
>>> Brian
>> 
>> A few years ago we were told by vendors that many router implementations
>> of IPsec were available only to traffic passing through a router, not to
>> the
>> control plane terminating in a router. Unless that has changed, IPsec is
>> not a good candidate here.
> 
> FWIW, that was an artifact of the IPsec requirements for routers. 4301 has 
> the following requirements:
> 
> (end sec 4.1, RFC 4301):
>   In summary,
> 
>   a) A host implementation of IPsec MUST support both transport and
>      tunnel mode.  This is true for native, BITS, and BITW
>      implementations for hosts.
> 
>   b) A security gateway MUST support tunnel mode and MAY support
>      transport mode.  If it supports transport mode, that should be
>      used only when the security gateway is acting as a host, e.g., for
>      network management, or to provide security between two
>      intermediate systems along a path.
> 
> A gateway acts as a host for all its routing protocol connections, and thus 
> its control plane should have to comply with (a).
> 
> I agree, that's why IPsec isn't a good choice to protect BGP, but we sort of 
> created that situation in 4301, AFAICT.
> 
> Joe

I won't quibble with that argument as far as protecting BGP. But for the 
"router-to-server" protocol described by this draft is actually acting as a 
host for the exchange. There are more router IPsec implementations that can 
protect the control plane now, and meeting the requirements above would likely 
be doable.

Brian


-- 
Brian Weis
Security Standards and Technology, SRTG, Cisco Systems
Telephone: +1 408 526 4796
Email: [email protected]





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