I am having lots of these messages on mail.log: Apr 20 14:17:15 ns24815 postfix/smtp: certificate verification failed for tnetmx.telefonica.net[184.108.40.206]:25: untrusted issuer /C=US/O=RTFM, Inc./OU=Widgets Division/CN=Test CA20010517 Apr 20 14:23:42 ns24815 postfix/smtp: certificate verification failed for mail.elventorro.net[220.127.116.11]:25: self-signed certificate Seems that server does not recognize the CA, should i add those certificates? is something to worry about? And what about this entries... connections without sending data ... Apr 20 14:02:06 ns24815 postfix/smtpd: lost connection after DATA (0 bytes) from cpe-98-28-208-132.woh.res.rr.com[18.104.22.168] Apr 20 14:02:07 ns24815 postfix/smtpd: lost connection after DATA (0 bytes) from 22.214.171.124.dynamic.adsl.gvt.net.br[126.96.36.199] Could be spammers checking relays? Any help or comment would be appreciatted . Thks in advanced.