Re: Urgent! Need help with abuse-detection and prevention

2004-05-11 Thread Adrian 'Dagurashibanipal' von Bidder
On Monday 10 May 2004 23.23, Peter Klein wrote:
> Hi guys,
>
> I've lately experienced excessive Apache-usage (to be clear: several
> hundered open connections in a very short time) to one of my servers.
> And I believe that FTP etc. are also subject to similar attacks. For
> Apache it resulted in problems that all processes were in state
> "reading" without actually doing anything ... a simple but efficient
> DOS for the httpd-process, that also caused it to die immediately.
>
> Can you give me any suggestions how to set up basic
> iptables-filtering-rules easily and how to prevent such abusive
> connections?

You can do something like
# iptables -A INPUT -m state --state NEW \
-m limit --rate 5/s --limit-burst 50  -p tcp --dport www -j ACCEPT
# iptables -A INPUT -m state --state NEW -p tcp --dport www -j DENY

Be sure to adjust to your usual load. And of course, this will just 
prevent the load on the machine to go over the top, so that the 
requests that came through will be handled quickly. It will still let 
whoever wishes to DDOS your webserver for requests from the outside.

greetings
-- vbi

-- 
"Ho visto astronauti al ristorante chiedere il conto alla rovescia."
-- Da it.hobby.umorismo


pgp749bqGu9Wx.pgp
Description: signature


Re: Urgent! Need help with abuse-detection and prevention

2004-05-11 Thread Adrian 'Dagurashibanipal' von Bidder
On Monday 10 May 2004 23.23, Peter Klein wrote:
> Hi guys,
>
> I've lately experienced excessive Apache-usage (to be clear: several
> hundered open connections in a very short time) to one of my servers.
> And I believe that FTP etc. are also subject to similar attacks. For
> Apache it resulted in problems that all processes were in state
> "reading" without actually doing anything ... a simple but efficient
> DOS for the httpd-process, that also caused it to die immediately.
>
> Can you give me any suggestions how to set up basic
> iptables-filtering-rules easily and how to prevent such abusive
> connections?

You can do something like
# iptables -A INPUT -m state --state NEW \
-m limit --rate 5/s --limit-burst 50  -p tcp --dport www -j ACCEPT
# iptables -A INPUT -m state --state NEW -p tcp --dport www -j DENY

Be sure to adjust to your usual load. And of course, this will just 
prevent the load on the machine to go over the top, so that the 
requests that came through will be handled quickly. It will still let 
whoever wishes to DDOS your webserver for requests from the outside.

greetings
-- vbi

-- 
"Ho visto astronauti al ristorante chiedere il conto alla rovescia."
-- Da it.hobby.umorismo


pgp0.pgp
Description: signature


Urgent! Need help with abuse-detection and prevention

2004-05-10 Thread Peter Klein
Hi guys,
I've lately experienced excessive Apache-usage (to be clear: several 
hundered open connections in a very short time) to one of my servers. And I 
believe that FTP etc. are also subject to similar attacks. For Apache it 
resulted in problems that all processes were in state "reading" without 
actually doing anything ... a simple but efficient DOS for the 
httpd-process, that also caused it to die immediately.

Can you give me any suggestions how to set up basic iptables-filtering-rules 
easily and how to prevent such abusive connections?

Your urgent help would be really much appreciated. Kind regards,
Paul Bergdörfer
_
Die ultimative Fan-Seite für den MSN Messenger http://www.ilovemessenger.de 
Emoticons und Hintergründe kostenlos downloaden!




Urgent! Need help with abuse-detection and prevention

2004-05-10 Thread Peter Klein
Hi guys,

I've lately experienced excessive Apache-usage (to be clear: several 
hundered open connections in a very short time) to one of my servers. And I 
believe that FTP etc. are also subject to similar attacks. For Apache it 
resulted in problems that all processes were in state "reading" without 
actually doing anything ... a simple but efficient DOS for the 
httpd-process, that also caused it to die immediately.

Can you give me any suggestions how to set up basic iptables-filtering-rules 
easily and how to prevent such abusive connections?

Your urgent help would be really much appreciated. Kind regards,
Paul Bergdörfer
_
Die ultimative Fan-Seite für den MSN Messenger http://www.ilovemessenger.de 
Emoticons und Hintergründe kostenlos downloaden!

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