Zur Analysezwecken kann es manchmal hilfreich sein, die Kommunikation eines Dienstes in Echtzeit mitzuschneiden bzw. sich diese anzuschauen.
ngrep -W byline -iq '' tcp port 25 T 83.169.42.112:25 -> 122.170.120.94:33492 [AP] 220 blog.cscholz.io ESMTP Service. T 122.170.120.94:33492 -> 83.169.42.112:25 [AP] EHLO dsl-mum-static-ilp-094.120.170.122.airtelbroadband.in. T 83.169.42.112:25 -> 122.170.120.94:33492 [AP] 250-mx02.blog.cscholz.io. 250-PIPELINING. 250-SIZE. 250-ETRN. 250-STARTTLS. 250-AUTH DIGEST-MD5 PLAIN CRAM-MD5 LOGIN. 250-AUTH=DIGEST-MD5 PLAIN CRAM-MD5 LOGIN. 250-ENHANCEDSTATUSCODES. 250-8BITMIME. 250 DSN. T 122.170.120.94:33492 -> 83.169.42.112:25 [AP] MAIL FROM: <taoismssyw28@everythingnewark.com>. RCPT TO: <infoq@blog.cscholz.io>. RCPT TO: <infod@blog.cscholz.io>. RCPT TO: <infoq@blog.cscholz.io>. DATA. T 83.169.42.112:25 -> 122.170.120.94:33492 [AP] 250 2.1.0 Ok. 554 5.7.1 Service unavailable; Client host [122.170.120.94] blocked using zen.spamhaus.org; http://www.spamhaus.org/query/bl?ip=122.170.120.94. 554 5.7.1 Service unavailable; Client host [122.170.120.94] blocked using zen.spamhaus.org; http://www.spamhaus.org/query/bl?ip=122.170.120.94. 554 5.7.1 Service unavailable; Client host [122.170.120.94] blocked using zen.spamhaus.org; http://www.spamhaus.org/query/bl?ip=122.170.120.94. 554 5.5.1 Error: no valid recipients.