On Thu, September 20, 2012 11:10, m.roth@5-cent.us wrote:
I'm not real good with smtp, but it looks as though someone from Spain is trying to directly connect to your smtp server. Unless you know that they're legitimately using your system, I'd block that IP now.
The list of sources is far too long to include in a message to the list. Suffice to say that each IP address is automatically blocked for varying lengths of time following any failed attempt. What I am trying to discover is what in particular, if anything, caused this traffic to suddenly start hitting our external server and whether or not we should be concerned about a specific vulnerability.
This host is our last remaining Sendmail server. All the rest have been switched to Postfix. None of the other MX hosts are reporting this and so the questions arise: Is this an attack? Is it specifically directed at the Sendmail server or is it just a co-incidence?
On Thu, Sep 20, 2012 at 2:31 PM, James B. Byrne byrnejb@harte-lyne.ca wrote:
The list of sources is far too long to include in a message to the list. Suffice to say that each IP address is automatically blocked for varying lengths of time following any failed attempt. What I am trying to discover is what in particular, if anything, caused this traffic to suddenly start hitting our external server and whether or not we should be concerned about a specific vulnerability.
Where does it fit with the MX preference number ordering? If it is a higher value (lower priority) the others should be tried first so traffic might be an indication that other servers are unreachable or failing. However, it is a common ploy for spammers to try to send to the low priority target first on the chance that the spam filtering isn't as good as on the primary server(s).
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James B. Byrne -
Les Mikesell