It looks like somebody is trying to figure out my internal users as evidenced by log excerpts below. Is there something I could do to, if not prevent this, reduce it?
Thanks in advance Jul 29 15:00:14 mail postfix/smtpd[2448]: NOQUEUE: reject: RCPT from unknown[93.85.224.123]: 550 5.1.1 <atil...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<atoll...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @roulottes-moulin-de-cheni.com> to=<atil...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<WIVANTR> Jul 29 15:00:14 mail postfix/smtpd[2448]: NOQUEUE: filter: RCPT from unknown[93.85.224.123]: <unknown[93.85.224.123]>: Client host triggers FILTER dspam:dspam; from=<atoll...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @roulottes-moulin-de-cheni.com> to=<b...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<WIVANTR> Jul 29 15:00:14 mail postfix/smtpd[2448]: NOQUEUE: reject: RCPT from unknown[93.85.224.123]: 550 5.1.1 <b...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<atoll...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @roulottes-moulin-de-cheni.com> to=<b...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<WIVANTR> Jul 29 15:00:15 mail postfix/smtpd[2451]: NOQUEUE: filter: RCPT from unknown[93.85.224.123]: <unknown[93.85.224.123]>: Client host triggers FILTER dspam:dspam; from=<finise...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @rfstech.com> to=<conning...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<JYMQMAWNRE> Jul 29 15:00:15 mail postfix/smtpd[2451]: NOQUEUE: reject: RCPT from unknown[93.85.224.123]: 550 5.1.1 <conning...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<finise...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @rfstech.com> to=<conning...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<JYMQMAWNRE> Jul 29 15:00:15 mail postfix/smtpd[2448]: NOQUEUE: filter: RCPT from unknown[93.85.224.123]: <unknown[93.85.224.123]>: Client host triggers FILTER dspam:dspam; from=<pepyspzw...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @raflatac.com> to=<cl...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<WIVANTR> Jul 29 15:00:15 mail postfix/smtpd[2448]: NOQUEUE: reject: RCPT from unknown[93.85.224.123]: 550 5.1.1 <cl...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<pepyspzw...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @raflatac.com> to=<cl...<http://groups.google.com/groups/unlock?_done=/group/list.postfix.users/browse_thread/thread/97669f7672ab48be&msg=92eb2a9a642a1f0d> @abc.com> proto=SMTP helo=<WIVANTR>
