How to determine if it's spam?

Question

System administration

There are several sites, some or some of them send spam, I connected mail server logs, I open them 2 times in my life, I see some items, but I can’t understand if it is or not.

Jun 25 23:12:44 donroll sendmail[30571]: u5PKCh8e030571: from=www, size=10008, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:44 donroll sendmail[30571]: u5PKCh8e030571: [email protected], ctladdr=www (80/80), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=40008, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:44 donroll sendmail[30573]: u5PKCii3030573: from=www, size=10043, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:44 donroll sendmail[30573]: u5PKCii3030573: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=40043, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:45 donroll sendmail[30575]: u5PKCiZX030575: from=www, size=9938, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:45 donroll sendmail[30575]: u5PKCiZX030575: [email protected], ctladdr=www (80/80), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=39938, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:45 donroll sendmail[30577]: u5PKCjm1030577: from=www, size=9995, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:45 donroll sendmail[30577]: u5PKCjm1030577: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39995, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:45 donroll sendmail[30579]: u5PKCjAj030579: from=www, size=10073, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:45 donroll sendmail[30579]: u5PKCjAj030579: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=40073, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:46 donroll sendmail[30581]: u5PKCkfq030581: from=www, size=9928, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:46 donroll sendmail[30581]: u5PKCkfq030581: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39928, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:46 donroll sendmail[30583]: u5PKCkW7030583: from=www, size=10056, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:46 donroll sendmail[30583]: u5PKCkW7030583: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=40056, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:46 donroll sendmail[30585]: u5PKCkA6030585: from=www, size=10040, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:46 donroll sendmail[30585]: u5PKCkA6030585: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=40040, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:47 donroll sendmail[30587]: u5PKCldW030587: from=www, size=9913, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:47 donroll sendmail[30587]: u5PKCldW030587: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39913, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:48 donroll sendmail[30589]: u5PKClks030589: from=www, size=10046, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:48 donroll sendmail[30589]: u5PKClks030589: [email protected], ctladdr=www (80/80), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=40046, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:48 donroll sendmail[30591]: u5PKCmwq030591: from=www, size=9960, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:48 donroll sendmail[30591]: u5PKCmwq030591: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39960, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:48 donroll sendmail[30595]: u5PKCmxP030595: from=www, size=9952, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:48 donroll sendmail[30595]: u5PKCmxP030595: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39952, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:48 donroll sendmail[30597]: u5PKCmM5030597: from=www, size=9980, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:48 donroll sendmail[30597]: u5PKCmM5030597: [email protected], ctladdr=www (80/80), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=39980, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]
Jun 25 23:12:49 donroll sendmail[30600]: u5PKCmVG030600: from=www, size=9947, class=0, nrcpts=1, msgid=<[email protected]tay0s.xn--p1ai>, [email protected]
Jun 25 23:12:49 donroll sendmail[30600]: u5PKCmVG030600: [email protected], ctladdr=www (80/80), delay=00:00:01, xdelay=00:00:00, mailer=relay, pri=39947, relay=[127.0.0.1] [127.0.0.1], dsn=4.0.0, stat=Deferred: Connection refused by [127.0.0.1]

Answer 1

According to the logs, none of the listed letters was sent. If spam is sent, then it is not from this mail server, or it is just an error log.

Answer 2

How to determine if it's spam?

Use anti-spam filters (built-in and special) of any company that suits you.