[CentOS] SYD flood dropped on Sendmail (centos 4.x)
webmaster at ew3d.com
Thu Nov 20 20:24:22 UTC 2008
Chris Heiner wrote:
> My guys,
> My firewall seems to block an attack my Centos / Sendmail boxes on
> port 110. These servers require a reboot after each attack. My
> firewall says it’s blocked? Do I need to patch something on sendmail?
> Or is my firewall not doing its job (Sonicwall)? This is not the first
> time this has happened.
> 11/20/2008 02:53:04.864 - SYN flood attack dropped - 220.127.116.11,
> 48102 - 10.80.80.210, 110
> 11/20/2008 03:08:04.864 - SYN flood attack dropped - 18.104.22.168,
> 64955, greatcooks.biz - 10.80.80.220, 110
> 11/20/2008 03:23:08.864 - SYN flood attack dropped - 22.214.171.124,
> 43068, greatcooks.biz - 10.80.80.210, 110
> Any input would be much appreciated.
If these are to bogus email addresses, you might try letting sendmail
itself throttle the attacks. Look into sendmail's BAD_RCPT_THROTTLE.
This has done wonders for my systems.
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