我的 Centos 消息日志文件中有很多网络无法访问的行。他们似乎无法解析某些地址，我不知道为什么我的服务器首先必须解析它们。谁能让我知道这种错误的起源？我受到攻击了吗？
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving './DNSKEY/IN': 2001:503:ba3e::2:30#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving './NS/IN': 2001:503:ba3e::2:30#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving 'dlv.isc.org/DNSKEY/IN': 2001:500:48::1#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving 'dlv.isc.org/DNSKEY/IN': 2001:4f8:0:2::19#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving 'ns.isc.afilias-nst.info/A/IN': 2001:500:2f::f#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving 'ns.isc.afilias-nst.info/AAAA/IN': 2001:500:2f::f#53
Oct 23 11:39:03 server named[1585]: error (network unreachable) resolving 'ns.isc.afilias-nst.info/A/IN': 2001:500:1::803f:235#53 …postfix check如果我在我的 Debian squeeze 服务器上运行，我会得到以下信息：
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_nisplus-2.11.3.so and /lib/libnss_nisplus-2.11.3.so differ
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_files-2.11.3.so and /lib/libnss_files-2.11.3.so differ
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_compat-2.11.3.so and /lib/libnss_compat-2.11.3.so differ
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_hesiod-2.11.3.so and /lib/libnss_hesiod-2.11.3.so differ
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_nis-2.11.3.so and /lib/libnss_nis-2.11.3.so differ
postfix/postfix-script: warning: /var/spool/postfix/lib/libnss_dns-2.11.3.so and /lib/libnss_dns-2.11.3.so differ
有人知道解决这个问题的解决方案吗？