[Cialug] rsync + SSH locking up?

[Nathan C. Smith]

I assume brute force.  Lots of wrong usernames and passwords.  Nothing that
*seems* to be working.

-Nate

-----Original Message-----
From: David Champion [mailto:dave at visionary.com] 
Sent: Friday, November 18, 2005 11:08 AM
To: Central Iowa Linux Users Group
Subject: Re: [Cialug] rsync + SSH locking up?


That could be... either way, if it's network latency or a DoS attack, 
tweaking the keepalive's might help.

Is there a specific SSH vulnerability you're referring to, or just the 
usual brute force attacks?

-dc

Nathan C. Smith wrote:
> Aren't there are a lot of SSH attacks going on right now too?  Could 
> be a DoS-type issue?
> 
> -----Original Message-----
> From: David Champion [mailto:dave at visionary.com]
> Sent: Friday, November 18, 2005 10:48 AM
> To: Central Iowa Linux Users Group
> Subject: Re: [Cialug] rsync + SSH locking up?
> 
> 
> Do a "man ssh" and look at the options for ServerAliveInterval and
> ServerAliveCountMax. I've used those and they seem to make SSH 
> connections a bit more robust.
> 
> Putty has this also, in the settings under "Connection", it's called
> "seconds between keepalives".
> 
> Not all SSH servers support these, OpenSSH does.
> 
> -dc
> 
> Bailey, Jonathan C wrote:
> 
>>I've seen the issue happen once in a while on a LAN, but mostly over
>>cable modem.
>>
>>ISPs with the issue:
>>Mediacom
>>Comcast
>>Marshallnet (server is at Marshallnet)
>>
>>I'm at a loss at the moment for this one.. It happens internally - no
>>errors or anything else. I'll try your loop and see if that helps.
>>
>>
>>Jon
>>
>>-----Original Message-----
>>From: cialug-bounces at cialug.org [mailto:cialug-bounces at cialug.org] On
>>Behalf Of Kendall Bailey
>>Sent: Friday, November 18, 2005 10:24 AM
>>To: Central Iowa Linux Users Group
>>Subject: Re: [Cialug] rsync + SSH locking up?
>>
>>I use mediacom cable internet, and long transfers of any kind often
>>hang.  I don't think rsync+ssh is any less reliable than wget in my 
>>experience, and I use both quite a bit.  With rsync, I use a loop and 
>>set a timeout and keep trying until it succeeds, like so
>>
>>while true ; do
>>   rsync --timeout=45 --rsh=ssh -avz <source> <dest>
>>   if [ $? -eq 0 ] ; then break ; fi
>>done
>>
>>I set up an ssh-agent and use public key auth so that a password isn't
>>needed each time through the loop.
>>
>>For simple wget, I use something like
>>
>>wget -c --read-timeout=45 <url>
>>
>>If something hangs for several seconds, it's been my experience that
>>it does not recover.  I have no idea what to blame, my box, mediacom, 
>>some intermediate router(s) or what?  I can tranfer gigs around my 
>>home network with no problems, using rsync+ssh.
>>
>>Can you give more detail?  Are you having trouble on a LAN or across
>>the internet?
>>
>>Kendall
>>
>>
>>On 11/17/05, Bailey, Jonathan C <bailj0 at bp.com> wrote:
>>
>>
>>>Has anyone on the list ever had an issue with rsync + SSH where the 
>>>connection hangs after about an hour of transfer? I've seen this 
>>>issue
>>
>>
>>>on different boxes and different configs (all debian-based). Is this 
>>>some sort of SSH setting or something else?
>>>
>>>
>>>
>>>------------------------------
>>>Server (n.),
>>>  1. Large, extremely expensive machine that goes "Ping!". Measuring 
>>>at least 25 cubic feet, heavy, bulky and giving of more heat then a 
>>>nuclear power plant. It's big, it's bad, it's beautiful and makes it 
>>>pretty obvious what happened to this year's IT-budget.
>>>
>>>Jonathan C Bailey | Elite Customer Solutions USA | Customer Care - 
>>>POS
>>
>>
>>>|
>>>(888) BP-HELP-U | (630) 300-5301 x5301 | 150 W Warrenville Rd, MC 
>>>200-1011T, Naperville, IL


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