BIND 9.2.0 Release Notes

Installation Information
Compatibility with Previous Versions of BIND
Chapter 2 37
Compatibility with Previous Versions of BIND
This section provides the BIND 9.2.0 compatibility information.
BIND 4.9.7 Compatibility
This section discusses the BIND 9.2.0-BIND 4.9.7 compatibility.
• BIND 9.2.0 uses a system assigned port for the UDP queries it
makes rather than port 53 that BIND 4.9.7 uses. This may conflict
with some firewalls.
To specify a port, edit the /etc/named.conf file as follows:
query-source address * port 53;
transfer-source * port 53;
notify-source * port 53;
• BIND 9.2.0 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 an explicit TTL. The hosts_to_named script will
create TTL value in the db files.
• BIND 9.2.0 does not support multiple CNAMEs with the same owner
name. For example:
www.example.com. CNAME host1.example.com.
www.example.com. CNAME host2.example.com.
In the above example, multiple records with the same owner name
“www.example.com” are not supported.
The named-checkzone program can be used to check the correctness
of the database files.
• BIND 9.2.0 does not support "CNAMEs with other data" with the
same owner name, ignoring the DNSSEC records (SIG, NXT, KEY)
that BIND 4.9.7 did not support. For example:
www.example.com. CNAME host1.example.com.
www.example.com. MX 10 host2.example.com.
• BIND 9.2.0 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.