Hi All, I am wondering if anyone is having similar experince with Listserv where messages send to a very large list get resend a second time to some of the recipientsc by sendmail due to unknown email addresses retuned by the server local alias table. We have configured our Listserv server in Unix environment and all our staff aliases are resolvable by the Listserv server. According to Lsoft technical support, we have to modify some setting in sendmail timeout to fix the issue, but they have not benn specific about the changes. During email distribution from Listserv, we noted that some of the recipients addreses that are bad are reported back instantly to Listserv by the server alias deamon as shown below. 9 May 2007 15:01:27 Processed 700 recipients... 9 May 2007 15:01:28 Processed 800 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:28 Processed 900 recipients... 9 May 2007 15:01:28 Processed 1000 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:28 Processed 1100 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:28 Processed 1200 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:28 Processed 1300 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:29 Processed 1400 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:29 Processed 1500 recipients... -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown -> RCPT TO:<[log in to unmask]> 550 5.1.1 <[log in to unmask]>... User unknown 9 May 2007 15:01:30 Processed 1600 recipients... 9 May 2007 15:01:30 Processed 1700 recipients... In Sendmail log the same message was generated twice to the same list with differennt message ID and each list of recipients are identical starting with the bad addreses. Please respond with any helpful information. Thanks, Nick