Windows EventLog 1035 --> Default Frontend MailServer

asked 2023-01-09T10:31:37.763+00:00
MikeZetPL 21 Reputation points

Hello.
In my small company we use single Exchange 2016 CU23 Server [>100 users].
Since some days I'm facing with receive many errors in Windows EventLog 1035 from Default Frontend
MailServer:
277367-eventlog.png

After check many Exchange logs I found some interesting part in FrontendTransport --> SmtpReceive logs when this log in WinEventLog is registred in the same time. Part of this exchange log is here:
277412-default-frontend-log.txt

My all receive connectors are:
277413-receiveconnectors-all.png

Security of my Default Frontend MailServer looks like this:
277398-receiveconnectorconf-sec.png

So my main questions for this topic are:

  1. Can this somehow avoided with better config of Default Frontend receive connector?
  2. Or rather is an security issue and communication need to be better protect for example on external firewall?
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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Accepted answer
  1. answered 2023-01-10T02:09:35.18+00:00
    Kael Yao-MSFT 21,521 Reputation points Microsoft Employee

    Hi @MikeZetPL

    Can this somehow avoided with better config of Default Frontend receive connector?

    It is not recommended to modify the settings of the five default receive connectors (including the Default Frontend receive connector).
    I would suggest just leave it as the default setting to avoid issues.

    Or rather is an security issue and communication need to be better protect for example on external firewall?

    To me this may seem like probes or script attacks.
    If you have found a large amount of suspicious requests from some specific ip addresses, please consider blocking these ip addresses on your firewall.


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