Distribution List Name:  PakDL@exchaneg.com
     Members:               User1,user2,user3
1-when some one mail from external domain(eg, gmail.com,hotmail.com) to members(user1@exchaneg.com,user2@exchaneg.com,user3@exchaneg.com) of the distribution list then the mail receiev to the member(user1@exchaneg.com,user2@exchaneg.com,user3@exchaneg.com) of the distribution list normail as distribution list working.

2-when some one mail from external domain(eg, gmail.com,hotmail.com) to PakDL@exchnage.com then the distribution list(PakDL@exchaneg.com) block the email from gmail.com and receive from hotmail.com

Hi ,

Please use the below mentioned command against that DL and check the results .

set-distributiongroup -identity "name of the distribution group" -RequireSenderAuthenticationEnabled $false  

Moreover please share us the NDR which is received at the sender end .

If you want only certain email domains to email your distribution group then set up a transport rule to block all incoming external email and exclude just the domains you want to allow.

Thanks.

Hi,

Try this transport rule.

Best Regards.