DNS_updates_and_zone_transfers_with_TSIG

DNS_updates_and_zone_transfers_with_TSIG#

DNS updates and zone transfers with TSIG#

FreeIPA doesn’t have support for TSIG in user interface but it can be configured to use TSIG for dynamic updates and zone transfers.

TSIG key configuration#

Generate a new TSIG key#

$ dnssec-keygen -a HMAC-SHA512 -b 512 -n HOST keyname
Kkeyname.+165+03160

Copy and paste key from key file to named.conf#

$ cat Kkeyname.+165+0316.private
Private-key-format: v1.3
Algorithm: 165 (HMAC_SHA512)
Key: keyvalue
Bits: AAA=

$ vim /etc/named.conf
key "keyname" {
       algorithm hmac-sha512;
       secret "keyvalue";
};

You have to repeat this copy&paste step for every FreeIPA server.

Dynamic updates#

Server#

Normal rules for BIND dynamic update policies apply. Just use name of the key you defined in named.conf:

$ ipa dnszone-mod example.com. --update-policy="grant keyname name example.com A;"

One of FreeIPA specifics is that dynamic updates can be completely disabled by switch even if update policy is non-empty. Make sure that DNS dynamic updates are enabled for your zone:

$ ipa dnszone-mod example.com. --dynamic-update=1

Client#

For nsupdate from bind-utils package you have to either use option -y algorithm:keyname:keyvalue or -k keyfilename option. E.g.

$ nsupdate -y hmac-sha512:keyname:keyvalue

or

$ nsupdate -k Kkeyname.+165+0316.private

Zone transfers#

Server#

FreeIPA user interface will not allow you to configure allow-transfer policy directly because it expects that allow-transfer consists only of IP addresses. You have to modify LDAP directly.

Run this on one of FreeIPA servers:

$ kinit admin
$ ldapmodify -Y GSSAPI << EOF
dn: idnsname=example.com.,cn=dns,dc=ipa,dc=example
changetype: modify
replace: idnsAllowTransfer
idnsAllowTransfer: key keyname;
-
EOF

Don’t forget to replace zone name in idnsname component of DN and realm name in dc=ipa,dc=example components.

Client#

The syntax for dig from bind-utils package is the same as for nsupdate. You have to either use option -y algorithm:keyname:keyvalue or -k keyfilename option. E.g.

$ dig -y hmac-sha512:keyname:keyvalue

or

$ dig -k Kkeyname.+165+0316.private

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