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Date:      Thu, 06 Dec 2001 06:48:51 -0800 (PST)
From:      Jonathan Hanna <jhanna@shaw.ca>
To:        Kal Torak <kaltorak@quake.com.au>
Cc:        FreeBSD Stable <freebsd-stable@FreeBSD.ORG>, FreeBSD ISP <freebsd-isp@FreeBSD.ORG>, Doug Silver <dsilver@quantified.com>
Subject:   Re: Whats with this -> sendto: No buffer space available
Message-ID:  <200112061448.fB6Empr27650@h24-79-126-98.vc.shawcable.net>
In-Reply-To: <3C0F1E30.3040508@quake.com.au>

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On 06-Dec-01 Kal Torak wrote:
> Doug Silver wrote:
> 
>> It happens all the time on one of my nameservers, but only when amanda is
>> trying to back it up.  Then it says this:
>> 
>> 
>>>Dec  4 23:00:43 HOST syslogd: sendto: No buffer space available
>>>Dec  5 00:00:36 HOST syslogd: sendto: No buffer space available
>>>
>> 
>> It does not affect the machine other than this message.
> 
> Hmmm, no affect???
> 
> When ever I get this message the machine can no longer send any data
> to the network on that interface... The interface has to be reset...
> 
> Perhaps the cause of your message is due to lack of mbufs for the load
> its getting, you should probably increase them...
> 
> The problem the rest of us have is different... I am almost 100% sure
> this is being caused by a problem upstream, the data cant get out so
> the sendto buffer fills and seems to lock up the interface... I have a
> feeling this may be specific to PPP connections, anyone finding this
> locks there interface on a non PPP connection??? (pppoe is still ppp
> could this even be specific to pppoe??)
> 
> Anyway to my way of thinking this is an error in the handeling of this
> kind of situation and needs to be looked at... Is there anything that
> I can log or dump next time this happens that would be helpfull in fixing
> this???

No PPP involved with me, and I think with many others. I agree that the
"no affect" above does look like ordinary buffer exhaustion, though I also have
a working network except for one interface (or maybe divert socket?).

A message that seems not to have made it to the list:

From: Freddie Cash <fcash@ocis.net>
To: Jonathan Hanna <jhanna@shaw.ca>
Subject: Re: Whats with this -> sendto: No buffer space available
Cc: freebsd-isp@freebsd.org

...

On December 5, 2001 12:46 am, you wrote:
> Anyone here of more progress on this problem?

> I had one case where a restart of natd fixed it. The
> ipfw rules were also flushed and reset as part of that.
> I am on semi-static DHCP with the appropriate natd arguments.

We've run into this problem quite often.  We have a dozen or so FreeBSD 
4.x boxes set up as NAT/ipfw firewall/gateways with 3C509B cards.  
Every so often, the links will just die and the only way to bring it 
back is to down the card for a couple seconds to clear the buffers.

The cause, for us, appears to be these wonderful viral worms 
propagating through Outlook.  A flurry of outgoing connections are 
made, NAT'd on the internal card, and nothing comes back, filling the 
buffer and blocking all outbound traffic.  Fortunately, the external 
card continues to work and we can log in remotely to restart the card, 
scan the logs, and track down the infected computer.

It's still a royal pain in the arse, though.  :)  Damn, I really wish 
people would smarten up and not open every single piece of mail they 
get.

PS:  This might not make it to the list as the reverse DNS on our main 
NAT box is hooped.  Could you forward this to the isp@ list if it 
doesn't show up there shortly?  Thanks.

-- 
Cheers,
Freddie _ _ _ _ _ _ _ _ _ _ PhoenixTek Consulting
fcash@bigfoot.com _ _ _ _ _ Unix, Network, Security Administration
_ _ _ _ _ _ _ _ _ _ _ _ _ _ (250) 376-5885


Jonathan Hanna <jhanna@shaw.ca>


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