Yes, sendmail is queries to port 113 on my firewall box. On this box no auth is running. Not accepting these queries results in much slower down-/upload of mails. Since on the firewall box is no auth server installed I don't see a real threat. So I let it be. I classified it problem no 3742978237 on my to do list.

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Disable it, if that is your problem. Or am I misreading anything?

No, you're not. If, then I have to disable it on sendmail first and afterwards on the firewall box.

So disable it in sendmail.cf: # timeouts (many of these) .... O Timeout.ident=0s Although, I'm not really sure if that did all the trick. Because I think I remember that I still had 113-queries from sendmail. Maybe someone else knows... Hope that helps Raffy