This raises the router, dns and nat64 lifetimes from 30 minutes to 60
minutes and lowers the prefix valid lifetime from 90 minutes to 60
minutes.

This brings us in line with the values of draft-ietf-6man-slaac-renum
which is going to be published as an RFC soon.

Aligning all these lifetimes to a single value (60 minutes) makes
sense because the information is transmitted in one router
advertisement packet. It does not make sense for one piece of
information to time out before another.

OK?

diff --git rad.c rad.c
index ae073db1758..6d136372640 100644
--- rad.c
+++ rad.c
@@ -765,7 +765,7 @@ config_new_empty(void)
 	xconf->ra_options.retrans_timer = 0;
 	xconf->ra_options.source_link_addr = 1;
 	xconf->ra_options.mtu = 0;
-	xconf->ra_options.rdns_lifetime = DEFAULT_RDNS_LIFETIME;
+	xconf->ra_options.rdns_lifetime = ADV_DEFAULT_LIFETIME;
 	SIMPLEQ_INIT(&xconf->ra_options.ra_rdnss_list);
 	SIMPLEQ_INIT(&xconf->ra_options.ra_dnssl_list);
 	SIMPLEQ_INIT(&xconf->ra_options.ra_pref64_list);
diff --git rad.conf.5 rad.conf.5
index 2ea87e186cb..f7b24f9459a 100644
--- rad.conf.5
+++ rad.conf.5
@@ -91,7 +91,7 @@ is optional:
 .It Cm lifetime Ar seconds
 The number of seconds the dns options are valid after receiving a router
 advertisement message.
-The default is 1800 seconds.
+The default is 3600 seconds.
 .It Cm nameserver Pq Ar address Ns | Ns Brq Ar address ...
 IPv6 address or list of IPv6 addresses of DNS name servers.
 .It Cm search Pq Ar domain Ns | Ns Brq Ar domain ...
@@ -129,7 +129,7 @@ The number of seconds the nat64 prefix option is valid after receiving a router
 advertisement message.
 A value of zero indicates to not use the prefix anymore.
 The maximum is 65528 seconds.
-The default is 1800 seconds.
+The default is 3600 seconds.
 .El
 .It Ic other configuration Pq Cm yes Ns | Ns Cm no
 If set to
@@ -141,7 +141,7 @@ The default is
 .It Ic router lifetime Ar seconds
 The number of seconds this router is a valid default router after receiving
 a router advertisement message.
-The default is 1800 seconds.
+The default is 3600 seconds.
 .It Ic router preference Pq Cm high Ns | Ns Cm medium Ns | Ns Cm low
 Indicate whether to prefer this router over other default routers.
 The default is
@@ -211,7 +211,7 @@ and it has a lower preferred lifetime.
 .It Cm valid lifetime Ar seconds
 The valid lifetime (vltime) in seconds for addresses generated from this
 prefix.
-The default is 5400.
+The default is 3600.
 This option is ignored if the prefix is discovered from a network interface
 and it has a lower valid lifetime.
 .El
diff --git rad.h rad.h
index a18d156b2d9..9f87a532732 100644
--- rad.h
+++ rad.h
@@ -28,13 +28,12 @@
 
 #define	MAX_RTR_ADV_INTERVAL	600
 #define	MIN_RTR_ADV_INTERVAL	200
-#define	ADV_DEFAULT_LIFETIME	3 * MAX_RTR_ADV_INTERVAL
 #define	ADV_PREFERRED_LIFETIME	2700	/* 45 minutes */
-#define	ADV_VALID_LIFETIME	5400	/* 90 minutes */
+#define	ADV_VALID_LIFETIME	3600	/* 60 minutes */
+#define	ADV_DEFAULT_LIFETIME	ADV_VALID_LIFETIME
 #define	MAX_RA_DELAY_TIME	500	/* 500 milliseconds */
 #define	MIN_DELAY_BETWEEN_RAS	3	/* 3 seconds */
 #define	MAX_SEARCH		1025	/* MAXDNAME in arpa/nameser.h */
-#define	DEFAULT_RDNS_LIFETIME	3 * MAX_RTR_ADV_INTERVAL
 
 #define	IMSG_DATA_SIZE(imsg)	((imsg).hdr.len - IMSG_HEADER_SIZE)
 

-- 
In my defence, I have been left unsupervised.