on 11-20-2008 3:31 PM Kai Schaetzl spake the following: > Chris Heiner wrote on Thu, 20 Nov 2008 13:43:44 -0800: > >> I get complaints about "the servers asking for username and password". > > from your users or what? Of course, they may complain. A big dictionary > attack can take almost all the bandwidth for some time or leave a backlog > of dovecot instances. > Please, as I understand you are a server adminstrator for quite a few > machines, correct? Yet, you are answering in a way as if you just brought > your first server online. > > Btw, it's a *SYN* flood, not a SYD flood and that won't change even if you > repeat it again and again. > > I >> started test@ accounts all many servers to try and track it down. > > Pardon, you did what? > >> I have tried restarting POP and SMTP in the past > > You may want to kill all dovecot instances, in case you *are* running > dovecot (if not, then of what you use, but I know that dovecot likes to > hang in this way if hammered). Just restarting it may not kill the backlog > of hanging connections. A "ps ax|grep login" would help to see if > instances are still running. > Restarting SMTP: again, this has nothing to do with SMTP! > > Kai > CentOS 4 comes with a very OLD version of dovecot. If you are using dovecot, you can get a much newer version at atrpms.net. The upgrade might be all you need to fix it. -- MailScanner is like deodorant... You hope everybody uses it, and you notice quickly if they don't!!!!
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