Hello Iam not shure if this are normal? In my postfix log this message appair now 2 days.
* Debian 9 - postfix = 3.1.14 May 29 00:59:22 mail postfix/smtpd[12989]: warning: hostname net6-ip74.linkbg.com does not resolve to address 87.246.7.74: Name or service not known May 29 00:59:43 mail postfix/smtpd[12781]: warning: hostname net6-ip70.linkbg.com does not resolve to address 87.246.7.70: Name or service not known May 29 00:59:44 mail postfix/smtpd[12989]: warning: hostname net6-ip66.linkbg.com does not resolve to address 87.246.7.66: Name or service not known May 29 01:00:07 mail postfix/smtpd[12989]: warning: hostname net6-ip74.linkbg.com does not resolve to address 87.246.7.74: Name or service not known May 29 01:00:30 mail postfix/smtpd[12781]: warning: hostname net6-ip70.linkbg.com does not resolve to address 87.246.7.70: Name or service not known May 29 01:00:30 mail postfix/smtpd[12926]: warning: hostname net6-ip66.linkbg.com does not resolve to address 87.246.7.66: Name or service not known rootl:/var/log# nslookup 87.246.7.74 Server: 46.38.225.230 Address: 46.38.225.230#53 Non-authoritative answer: 74.7.246.87.in-addr.arpa canonical name = 74.0-255.7.246.87.in-addr.arpa. 74.0-255.7.246.87.in-addr.arpa name = net6-ip74.linkbg.com. Authoritative answers can be found from: 0-255.7.246.87.in-addr.arpa nameserver = sns.linkbg.com. 0-255.7.246.87.in-addr.arpa nameserver = pns.linkbg.com. pns.linkbg.com internet address = 89.215.246.2 sns.linkbg.com internet address = 89.215.246.3 Thanks for any possible Update Mauri
