Long delay during login

Rob Landley rob at landley.net
Mon Oct 24 06:23:19 WST 2011


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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