{"id":85,"date":"2017-10-10T07:43:00","date_gmt":"2017-10-10T07:43:00","guid":{"rendered":"https:\/\/linuxadmin.melberi.com\/uncategorized\/lost-input-channel-from-to-mta-after"},"modified":"2017-10-10T12:10:29","modified_gmt":"2017-10-10T12:10:29","slug":"lost-input-channel-from-mta","status":"publish","type":"post","link":"https:\/\/www.melberi.com\/linuxadmin\/sendmail\/lost-input-channel-from-mta","title":{"rendered":"Lost input channel from localhost to MTA after rcpt Sendmail"},"content":{"rendered":"

Sendmail Error Message Lost input channel from to MTA after rcpt<\/p>\n

Error Message:<\/u><\/h3>\n

Jun 18 10:40:12 MailServer sendmail[17012]: r5S59J7h017012: lost input channel from<\/b> mail.domain.com [x.x.x.x] to MTA after rcpt<\/b>
\nJun 18 10:40:12 MailServer sendmail[17012]: r5S59J7h017012: from=, size=0, class=0, nrcpts=1, proto=SMTP, daemon=MTA, relay=mail.domain.com [x.x.x.x]<\/p>\n

Solution:<\/u><\/h3>\n

By adding the IP address or domain names of the rejected mail servers in the Access map, you can ignore this error message.
\nedit \/etc\/mail\/access<\/p>\n

x.x.x.x\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 OK<\/b>
\nfrom:mail.domain.com\u00a0 OK<\/b><\/p>\n

Or
\nBy disabling the delay check and DNSBL feature<\/b> in sendmail.mc file you can ignore this error message.<\/p>\n

FEATURE(delay_checks)dnl<\/p>\n

FEATURE(dnsbl, `relays.ordb.org’, `Rejected – see http:\/\/ordb.org\/’)dnl
\nFEATURE(dnsbl, `list.dsbl.org’, `Rejected – see http:\/\/dsbl.org\/’)dnl
\nFEATURE(dnsbl, `relays.visi.com’, `Rejected – see http:\/\/relays.visi.com\/’)dnl
\nFEATURE(dnsbl, `bl.spamcop.net’, `Rejected – see http:\/\/bl.spamcop.net\/’)dnl<\/p>\n

Delay All Check<\/u><\/h3>\n

By using FEATURE(`delay_checks’) the rulesets check_mail and check_relay will not be called when a client connects or issues a MAIL command, respectively. Instead, those rulesets will be called by the check_rcpt ruleset; they will be skipped if a sender has been authenticated using a “trusted” mechanism, i.e., one that is defined via TRUST_AUTH_MECH(). If check_mail returns an error then the RCPT TO command will be rejected with that error. If it returns some other result starting with $# then check_relay will be skipped. If the sender address (or a part of it) is listed in the access map and it has a RHS of OK or RELAY, then check_relay will be skipped.
\nThis has an interesting side effect: if your domain is my.domain and you have<\/p>\n

my.domain RELAY<\/p>\n

in the access map, then any e-mail with a sender address of will not be rejected by check_relay even though it would match the hostname or IP address<\/b>. This allows spammers to get around DNS based blacklist by faking the sender address. To avoid this problem you have to use tagged entries:<\/p>\n

To:my.domain RELAY
\nConnect:my.domain RELAY<\/p>\n

For more info read this\u00a0 <\/a><\/b><\/p>\n","protected":false},"excerpt":{"rendered":"

Sendmail Error Message Lost input channel from to MTA after rcpt Error Message: Jun 18 10:40:12 MailServer sendmail[17012]: r5S59J7h017012: lost input channel from mail.domain.com [x.x.x.x] to MTA after rcpt Jun… Read more »<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-85","post","type-post","status-publish","format-standard","hentry","category-sendmail"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t