Subject: [Tsvwg] Follow-up : Effects of port randomization with TCP TIME-WAIT state

From: "Anantha Ramaiah (ananth)" <[email-masked]>
Date: Sun, 3 Aug 2008 22:29:12 -0700

Hi,
   A presentation was made in Dublin (albeit short due to lack of time)
about the following draft  :

http://www.ietf.org/internet-drafts/draft-ananth-tsvwg-timewait-00.txt

[An email was sent to the alias describing the motivation for writing
this draft earlier)

And after that I talked to Lars offline about how to move forward on
this :-

Option #1 
=========
Merge the ideas listed by this draft into the existing port
randomization draft. 

(http://www.ietf.org/internet-drafts/draft-ietf-tsvwg-port-randomization
-01.txt)

Reasons :

- The port randomization draft is incomplete if it doesn't not address
and offer solutions  to the problems seen due to the TCB lingering in
TIME-WAIT state.

- FWIW, the port randomization draft DOES talk about TCP and it DOES
mention about port-reuse property and touches upon the TIME-WAIT state,
but doesn't offer a "fool proof" solution which addresses this issue.

- there have been some email exchanges when the draft was posted
initially ( a few weeks back) and Fernando hinted that he is going to
come up with an updated version of the draft. May be that version can
include the ideas listed in the timewait draft ?

Option #2
========

Take it to TCPM. We don't think this is a good idea since :

- the port randomization draft already talks about TIME-WAIT issue and
acknowledges the problem. A separate draft for this in a different WG
seems like an overkill.
- the current scope of the draft is limited ONLY to narrate the side
effects of doing port randomization. (For e.g.:- there are other issues
that can documented w.r.t TIME-WAIT state like timewait loading of busy
servers (Ted/Joe's paper) and hence the purpose of this attempt is to
keep it focused w.r.t to the current context viz., port randomization)

Hence our choice is to go with option #1. 

Ok, before even going that far, it would be nice if folks can give this
document a read and give their opinion.

Comments welcome.

Thanks,
-Anantha

---

From: Lars Eggert <[email-masked]>
Date: Wed, 6 Aug 2008 16:31:13 +0300

For the record, there is also option #3 - don't do anything.

(I'm not saying that's the option I'd prefer, I'm just saying that it  
is a valid choice.)

Lars

---

From: "Anantha Ramaiah (ananth)" <[email-masked]>
Date: Thu, 7 Aug 2008 07:57:10 -0700

Lars,

Few clarifications/comments inline..

> -----Original Message-----
> From: Lars Eggert [mailto:[email-masked]] 
> Sent: Wednesday, August 06, 2008 6:31 AM
> To: Anantha Ramaiah (ananth)
> Cc: [email-masked]; James Polk (jmpolk); 
> [email-masked]
> Subject: Re: Follow-up : Effects of port randomization with 
> TCP TIME-WAIT state
> 

Here is why I haven't listed that option to begin with:

The port randomization draft does mention about TIME-WAIT etc., the
current draft is only trying to elaborate and offer solutions to the
same. So, the concept is nothing new, it is completely related.

> 
> (I'm not saying that's the option I'd prefer, I'm just saying 
> that it is a valid choice.)

Sure, but I am confused as to where to draw the line, here. You email
comes across to me as suggesting that the port randomization draft, is
complete as it stands and we are trying to share the issues which we
faced after changing our implementation to allocate ports from
sequential to random which is very much related to the concepts
presented in the port randomization draft. 
 
-Anantha
> > mention about port-reuse property and touches upon the TIME-WAIT 
> > state, but doesn't offer a "fool proof" solution which 
> addresses this 
> > issue.
> >
> > effects of doing port randomization. (For e.g.:- there are other 
> > issues that can documented w.r.t TIME-WAIT state like 
> timewait loading 
> > of busy servers (Ted/Joe's paper) and hence the purpose of this 
> > attempt is to keep it focused w.r.t to the current context 
> viz., port 
> > randomization)
> >
> > Ok, before even going that far, it would be nice if folks can give 
> > this document a read and give their opinion.
> >
> > Comments welcome.
> >
> > Thanks,
> > -Anantha
> 
>

---

From: Lars Eggert <[email-masked]>
Date: Fri, 8 Aug 2008 09:40:23 +0300

Hi,

you're reading too much into my email. I was merely pointing out that  
in addition to your two options (change the part-randomization draft  
or publish something in TCPM) there is obviously also the possibility  
for the WGs involved to decide that nothing needs to be done.

(I do understand that you believe that this option 3 is not what  
should happen.)

Lars