Inbound authentication failed with error LogonDenied for Receive connector Default SERVERNAME. The authentication mechanism is Login

Hi all,
First I'll start by saying I'm an Exchange novice, so I'm a bit green when it comes to exchange in general.

Looking through the error and event logs, I noticed a bunch of the errors in the attached file.

Is this something to be concerned with? I am not familiar with the IP address listed, concerned someone is trying to hack in? or perhaps nothing to concerned about?

I also have seen the same error message with a different IP - 196.204.141.122

Thanks in advance
ERRORLOG.txt
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ChiITAsked:
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Simon Butler (Sembee)Connect With a Mentor ConsultantCommented:
Standard authenticated relaying attack. If you have your own server on the internet, then it happens. Just ensure that the usual targets for the attack (Administrator is the main one) has a strong password and they will not get in. Doesn't stop them trying - like you can't stop someone from hammering on your door to get in without the key!

Simon.
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Schuyler DorseyConnect With a Mentor Commented:
Without a layer7 applicable firewall or an IDS, I do not think there is much you can do to prevent this.

Alternatively, you could switch to a cloud based spam provider like AppRiver or Barracuda so your email hits the cloud then comes to your server. This way, you can set your firewall and Exchange to only allow inbound SMTP from your spam provider.

This is probably people trying to bruteforce their way in.
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ChiITAuthor Commented:
Thanks for responding, so is this typical when you see when you have your own exchange? We do have a local spam filter running and a Dell Sonicwall firewall.

I am familiar with appriver and barracudas services and was considering them. You mention someone trying to bruteforce, is this related to spam do you think? Or someone trying to hack in? Also since this is via smtp, am I right I saying they are using smtp to try and I that?


Big Apologies for all the questions...
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ChiITAuthor Commented:
thank you so much!
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