Hello Alex, Syslog-ng can be compiled with or without IPv6 support. As a first step please verify if it was compiled that way. If you start Syslog-ng with the "--version" option it will print a little debug information about itself. Among other options there will be a line: "Enable-IPv6" (If it was compiled with "Enable-IPv6: on", please copy the entire output here. It will help with the later investigation.) Best regards, Laci ________________________________ From: syslog-ng <syslog-ng-bounces@lists.balabit.hu> on behalf of Alexandre Santos <alexandre.rosas.santos@gmail.com> Sent: Friday, August 28, 2020 12:35 To: Syslog-ng users' and developers' mailing list <syslog-ng@lists.balabit.hu> Subject: [syslog-ng] No remote logging with hostname which has address is IPv6 CAUTION: This email originated from outside of the organization. Do not follow guidance, click links, or open attachments unless you recognize the sender and know the content is safe. Hi, I have configuration, which is sending log messages to a remote hostname (dns6server). The particularity of this remote server is that it is resolved to an IPv6 address. ping works fine: root@localhost:~# ping dns6server -c 3 PING dns6server(2620:38:4::8:4000:238) 56 data bytes 64 bytes from 2620:38:4::8:4000:238: icmp_seq=1 ttl=63 time=0.354 ms 64 bytes from 2620:38:4::8:4000:238: icmp_seq=2 ttl=63 time=0.264 ms 64 bytes from 2620:38:4::8:4000:238: icmp_seq=3 ttl=63 time=0.310 ms But syslog-ng seems not to be able to resolve the ipv6 address: Aug 27 20:58:37 localhost systemd[1]: mgmt-syslog-ng.service: Succeeded. Aug 27 20:58:37 localhost systemd[1]: Stopped External Logger Daemon. Aug 27 20:58:37 localhost systemd[1]: Starting External Logger Daemon... Aug 27 20:58:37 localhost ip[32709]: [2020-08-27T20:58:37.841389] WARNING: With use-dns(no), dns-cache() will be forced to 'no' too!; Aug 27 20:58:46 localhost ip[32709]: [2020-08-27T20:58:46.854714] Error resolving hostname; host='dns6server' Aug 27 20:58:46 localhost ip[32709]: [2020-08-27T20:58:46.854758] Initiating connection failed, reconnecting; time_reopen='60' Aug 27 20:58:46 localhost systemd[1]: Started External Logger Daemon. Any Ideas? I am sending the configuration and debug log in attachment. Thanks in Advance, Alex