· 6 years ago · Jun 14, 2019, 10:32 PM
1Jun 14 17:46:44 $MYSERVER postfix/smtpd[24862]: NOQUEUE: reject: RCPT from unknown[209.85.210.52]: 450 4.1.8 <$ME@gmail.com>: Sender address rejected: Domain not found; from=<$ME@gmail.com> to=<$ME@$MYDOMAIN> proto=ESMTP helo=<mail-ot1-f52.google.com>
2
3Jun 14 17:46:44 $MYSERVER postfix/smtpd[24862]: warning: 52.210.85.209.zen.spamhaus.org: RBL lookup error: Host or domain name not found. Name service error for name=52.210.85.209.zen.spamhaus.org type=A: Host not found, try again
4
5> dig -x 209.85.210.52 +short
6mail-ot1-f52.google.com.
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8> dig gmail.com +short
9172.217.8.165
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11> ping -c 1 gmail.com
12PING gmail.com (172.217.8.197) 56(84) bytes of data.
1364 bytes from ord37s09-in-f5.1e100.net (172.217.8.197): icmp_seq=1 ttl=55 time=1.75 ms
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15--- gmail.com ping statistics ---
161 packets transmitted, 1 received, 0% packet loss, time 2ms
17rtt min/avg/max/mdev = 1.752/1.752/1.752/0.000 ms