Zabbix

...G...PS. [ZBX-10820] fixed potential loss of data when server/proxy processes zabbix_sender data
...G...PS. [ZBX-4252] eliminated sending of DNS AAAA queries when checking IPv4 incoming connection
                      in agent or for trapper item and A queries in case of IPv6

With this change:
   - after an incoming connection is established its peer IP address is
     obtained immediately, stored and used in all following checks and error
     reporting. If the peer IP address cannot be obtained the connection is
     closed.
   - buffer lengths have been increased from 64 to 256 bytes to prevent
     truncation of long DNS names when getting 'net.tcp.port',
     'net.tcp.service', 'net.tcp.service.perf', 'net.udp.service.perf'
     and 'net.udp.service' items.
   - ZBX-4252 "Agent sends AAAA queries when operating system IPv6 support is disabled" is fixed.
   - zbx_tcp_check_security() is refactored and renamed to zbx_tcp_check_allowed_peers() to better
     reflect its purpose.
   - getaddrinfo() in zbx_tcp_check_allowed_peers() now returns result only for TCP protocol,
     this eliminates unnecessary calls to zbx_ip_cmp().