Hello all. Several of our RHEL-servers are issuing strange DNS lookups. Consider this example: * 1 0.000000 1.2.3.4 -> 5.6.7.8 DNS Standard query AAAA ** server1.example-prod.com* <http://server1.example-prod.com/>* 9 0.007891 1.2.3.4 -> 5.6.7.8 DNS Standard query AAAA server1.example-prod.com.example-test.local 11 0.092904 1.2.3.4 -> 5.6.7.82 DNS Standard query A server1.example-prod.com 12 0.093356 5.6.7.8 -> 1.2.3.4 DNS Standard query response A 1.2.3.4 * >From what I can tell, the client first issues two IPv6 DNS lookups, before falling back to IPv4 lookup. We're not running IPv6 (and our DNS servers do not support IPv6 lookups), so the client is not getting and answer before issuing the IPv4 lookup. I've very puzzled by the second query, in which the FQDN of the lookup query is appended another domain. I've noticed that the appended domain may be both the same domain name (i.e. server1.example-prod-com.example-prod.com) or another domain as in the example above. Does anyone have a clue as to why such bizarre queries are performed by the client? Since we're not running IPv6, I have simply disabled it for this server (grepping "lsmod" does not return any "ipv6" results). Yet the problem remains. Does the DNS lookup library automatically issue IPv6 queries before issuing IPv4 queries? Is there a way to disable IPv6 lookups? Regards, Kenneth Holter -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
