Copyright (C) Internet Systems Consortium, Inc. ("ISC") See COPYRIGHT in the source root or http://isc.org/copyright.html for terms. BIND 4 to BIND 9 Migration Notes To transition from BIND 4 to BIND 9 you first need to convert your configuration file to the new format. There is a conversion tool in contrib/named-bootconf that allows you to do this. named-bootconf.sh < /etc/named.boot > /etc/named.conf BIND 9 uses a system assigned port for the UDP queries it makes rather than port 53 that BIND 4 uses. This may conflict with some firewalls. The following directives in /etc/named.conf allows you to specify a port to use. query-source address * port 53; transfer-source * port 53; notify-source * port 53; BIND 9 no longer uses the minimum field to specify the TTL of records without a explicit TTL. Use the $TTL directive to specify a default TTL before the first record without a explicit TTL. $TTL 3600 @ IN SOA ns1.example.com. hostmaster.example.com. ( 2001021100 7200 1200 3600000 7200 ) BIND 9 does not support multiple CNAMEs with the same owner name. Illegal: www.example.com. CNAME host1.example.com. www.example.com. CNAME host2.example.com. BIND 9 does not support "CNAMEs with other data" with the same owner name, ignoring the DNSSEC records (SIG, NXT, KEY) that BIND 4 did not support. Illegal: www.example.com. CNAME host1.example.com. www.example.com. MX 10 host2.example.com. BIND 9 is less tolerant of errors in master files, so check your logs and fix any errors reported. The named-checkzone program can also be to check master files. Outgoing zone transfers now use the "many-answers" format by default. This format is not understood by certain old versions of BIND 4. You can work around this problem using the option "transfer-format one-answer;", but since these old versions all have known security problems, the correct fix is to upgrade the slave servers.