Do you see the sasl auth in the log? It should start like this:
Code:
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: connect from unknown[10.10.x.x]
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: setting up TLS connection from unknown[10.10.x.x]
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: SSL_accept:before/accept initialization
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: read from 08235638 [0823F1A8] (11 bytes => -1 (0xFFFFFFFF))
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: SSL_accept:error in SSLv2/v3 read client hello A
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: read from 08235638 [0823F1A8] (11 bytes => 11 (0xB))
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: 0000 16 03 01 00 53 01 00 00|4f 03 01 ....S... O..
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: read from 08235638 [0823F1B3] (77 bytes => -1 (0xFFFFFFFF))
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: SSL_accept:error in SSLv3 read client hello B
Mar 13 09:44:37 dogfood postfix/smtpd[18664]: SSL_accept:error in SSLv3 read client hello B