Please see inline.

 

On Wed, Aug 10, 2022 at 4:37 PM, Valery Smyslov < <mailto:s...@elvis.ru> 
s...@elvis.ru> wrote:

Hi Warren, 

thank you for this discussion, please see inline. 

Warren Kumari has entered the following ballot position for 
draft-ietf-ipsecme-rfc8229bis-07: Discuss 

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---------------------------------------------------------------------- DISCUSS: 
---------------------------------------------------------------------- 

Do not panic! 

By no means :-) 

This should be trivial to address, probably by pointing me at something that I 
missed (very likely), or by dropping in a sentence to two into the document. 

The document starts off with: "This document describes a method to transport 
Internet Key Exchange Protocol (IKE) and IPsec packets over a TCP connection 
for traversing network middleboxes that may block IKE negotiation over UDP." 

As far as I can tell (and again, it is likely that I missed something!) it 
doesn't really discuss the fact that the operator may be intentionally blocking 
IKE. For example, many enterprises really don't want their users to be building 
IPSec tunnels into/out of their network because they want to do DLP, 
firewalling, and so they block IKE to block IPSec. This may be a flawed 
concept, and you and I may think that it's a losing battle, but I really think 
that the document needs to at least discuss that this potentially bypasses 
intentional security controls. 

This document is not intended to provide a mechanism to bypass intentional 
security controls. 

 

Excellent!

 

 

In most cases IKE is blocked not because operators want do DLP etc., but 
because operators of small hotels, cafe, internet kiosks often block all UDP 
except DNS and sometimes block all TCP except http / https too.

 

Yup.

 

I can only imagine why they do it, my guess is "just in case". 

 

 

Yup, agreed.

 

 

This is a real problem and our experience shows that it's impossible to solve 
by an IPsec user who appeared in the situation when UDP is blocked in a hotel 
he stayed in.

 

 

Oh, yeah, I fully agree.

 

Operators wanting to block IKE because of security implications may also block 
TCP port 4500 and use DLP to filter out TCP streams started with IKETCP, so 
they can deal with this specification.

 

Yes, yes they can — but I suspect that many currently aren't.

 

What would satisfy me would be something like a sentence saying something along 
the lines of "Operators who intentionally want to block IKE because of security 
implications should also block TCP port 4500 and use DLP to filter out TCP 
streams started with IKETCP".

 

This seems like a simple addition to help prevent people shooting themselves in 
the foot (or, at least that we can point to if they do :-))

 

          I've added the following text at the end of the Middlebox 
Considerations section:

 

        Operators who intentionally block IPsec because of security 
implications 

        may want to also block TCP port 4500 or use DLP to filter out TCP 
connections started with IKETCP stream prefix.

        

          Is it OK? (Tommy will review the changes, so he may want to make some 
additional tweaks).

 

          Regards,

          Valery.

 

          

 

W

 

Besides, there may be future IKE extensions that rely on TCP transport 
(e.g. for transferring large PQ public keys, see 
draft-tjhai-ikev2-beyond-64k-limit). In this case TCP is used not because UDP 
is blocked, but because sending 1MB data over UDP with no congestion control is 
not a good idea. This is not yet a WG document, so it is not referenced in the 
draft, but we keep it in mind. 

Hope this helps. 

Regards, 
Valery. 

See: 
https://www.ietf.org/about/groups/iesg/statements/handling-ballot- positions/

 

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