Long delay during login

Peter Turczak peter at turczak.de
Tue Oct 25 21:38:51 WST 2011


Hi Rob,

a few years back in 2008 I did this port and announced it here. But it didn't seem to get much of a grip. You will find it's source here : http://peter.turczak.de/dropbear-tfm.tgz .

Maybe it may help out someone in dire need of a faster ssh-handshake ;).

Best regards,
  Peter

On Oct 24, 2011, at 12:23 AM, Rob Landley wrote:

> Where does one get such a port?  (Are there instructions?)
> 
> Rob
> 
> On 10/23/2011 09:28 AM, Avner Flesch wrote:
>> Hi,
>> 
>> I used dropbear that was ported to tomsfastmath library(instead of tommath).
>> I reduced the login delay on my machine (powerpc 8xx 50MHz) to 5 seconds!
>> 
>> I would like to reduce the delay more. Is anyone has any idea?
>> 
>> Thanks
>> 
>> Avner
>> 
>> -----Original Message-----
>> *From*: Avner Flesch <avnerf at web-silicon.com
>> <mailto:Avner%20Flesch%20%3cavnerf at web-silicon.com%3e>>
>> *To*: Rob Landley <rob at landley.net
>> <mailto:Rob%20Landley%20%3crob at landley.net%3e>>
>> *Cc*: Gary <gmart at coinet.com <mailto:Gary%20%3cgmart at coinet.com%3e>>,
>> dropbear at ucc.asn.au <mailto:dropbear at ucc.asn.au>
>> *Subject*: Re: Long delay during login
>> *Date*: Tue, 11 Oct 2011 18:05:01 +0200
>> 
>> Hi,
>> 
>> I have also the same issue with dropbear version 0.53.1 on powerpc 50MHz
>> 32bits the login took more then 30 seconds.
>> After I updated the libtomath library to version 0.42 and libtomcrypt
>> version to 1.17
>> I reduced the delay to 13 seconds.
>> 
>> But it still not enough - after a research I found that the delay is in
>> the routine "mp_exptmod_fast" from libtommath, there is a for(;;) loop
>> that take a while.
>> Is anyone know how can I overcome this issue?
>> 
>> Thanks
>> 
>> Avner
>> 
>> -----Original Message-----
>> *From*: Rob Landley <rob at landley.net
>> <mailto:Rob%20Landley%20%3crob at landley.net%3e>>
>> *To*: Gary <gmart at coinet.com <mailto:Gary%20%3cgmart at coinet.com%3e>>
>> *Cc*: dropbear at ucc.asn.au <mailto:dropbear at ucc.asn.au>
>> *Subject*: Re: Long delay during login
>> *Date*: Sat, 01 Oct 2011 14:00:28 -0500
>> 
>> On 09/28/2011 01:31 PM, Gary wrote:
>>> Matt Johnston <matt <at> ucc.asn.au> writes:
>>> 
>>> On Mon, Jun 13, 2005 at 10:21:53AM +0100, Simon Rowe wrote:
>>>> We're seeing a long delay when logging in using dropbear on to our embedded 
>>>> system (60MHz PowerPC). Looking at the debug from the client end it appears 
>>>> that the issue is the Diffie-Hellman key negotiation within dropbear
>>>> 
>>>> debug1: expecting SSH2_MSG_KEXDH_REPLY
>>>> 
>>>> [delay of about 8 seconds]
>>>> 
>>>> Is there anything we can change to reduce this delay?
>>> 
>>> 
>>> Same problem here.  My bet is that it's blocking on the random 
>>> device.  For me ssh'ng to a busy machine is fast, ssh'ng to an
>>> idle machine almost always has a BIG delay.
>> 
>> Switch from /dev/random to /dev/urandom perhaps?
>> 
>> Rob
>> 
>> 
>> 
>> 
> 



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