diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index 41a58b36eb..b263220e0c 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -2622,7 +2622,8 @@ Token=prefixstable:2002:da8:1::</programlisting></para>
         <term><varname>RouterLifetimeSec=</varname></term>
 
         <listitem><para>Takes a timespan. Configures the IPv6 router lifetime in seconds. When set to
-        0, the host is not acting as a router. Defaults to 30 minutes.</para>
+        0, the host is not acting as a router. The value must be 0 second, or between 4 seconds and
+        9000 seconds. Defaults to 1800 seconds (30 minutes).</para>
         </listitem>
       </varlistentry>
 
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 6631f5bc3e..595dd36121 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -331,7 +331,7 @@ DHCPv6PrefixDelegation.Assign,               config_parse_bool,
 DHCPv6PrefixDelegation.ManageTemporaryAddress, config_parse_bool,                                      0,                             offsetof(Network, dhcp6_pd_manage_temporary_address)
 DHCPv6PrefixDelegation.Token,                config_parse_address_generation_type,                     0,                             offsetof(Network, dhcp6_pd_tokens)
 DHCPv6PrefixDelegation.RouteMetric,          config_parse_uint32,                                      0,                             offsetof(Network, dhcp6_pd_route_metric)
-IPv6SendRA.RouterLifetimeSec,                config_parse_sec,                                         0,                             offsetof(Network, router_lifetime_usec)
+IPv6SendRA.RouterLifetimeSec,                config_parse_router_lifetime,                             0,                             offsetof(Network, router_lifetime_usec)
 IPv6SendRA.Managed,                          config_parse_bool,                                        0,                             offsetof(Network, router_managed)
 IPv6SendRA.OtherInformation,                 config_parse_bool,                                        0,                             offsetof(Network, router_other_information)
 IPv6SendRA.RouterPreference,                 config_parse_router_preference,                           0,                             0
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 5469cb4560..1f83a092c5 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -33,6 +33,7 @@
 #include "networkd-sriov.h"
 #include "parse-util.h"
 #include "path-lookup.h"
+#include "radv-internal.h"
 #include "set.h"
 #include "socket-util.h"
 #include "stat-util.h"
@@ -421,7 +422,7 @@ int network_load_one(Manager *manager, OrderedHashmap **networks, const char *fi
                 .dhcp_server_emit_router = true,
                 .dhcp_server_emit_timezone = true,
 
-                .router_lifetime_usec = 30 * USEC_PER_MINUTE,
+                .router_lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
                 .router_dns_lifetime_usec = 7 * USEC_PER_DAY,
                 .router_emit_dns = true,
                 .router_emit_domains = true,
diff --git a/src/network/networkd-radv.c b/src/network/networkd-radv.c
index 7b92e6c4f9..08a8bbf8da 100644
--- a/src/network/networkd-radv.c
+++ b/src/network/networkd-radv.c
@@ -17,6 +17,7 @@
 #include "networkd-radv.h"
 #include "networkd-route.h"
 #include "parse-util.h"
+#include "radv-internal.h"
 #include "string-util.h"
 #include "string-table.h"
 #include "strv.h"
@@ -1256,6 +1257,58 @@ int config_parse_router_prefix_delegation(
         return 0;
 }
 
+int config_parse_router_lifetime(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        usec_t usec, *lifetime = data;
+        int r;
+
+        assert(filename);
+        assert(section);
+        assert(lvalue);
+        assert(rvalue);
+        assert(data);
+
+        if (isempty(rvalue)) {
+                *lifetime = RADV_DEFAULT_ROUTER_LIFETIME_USEC;
+                return 0;
+        }
+
+        r = parse_sec(rvalue, &usec);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Failed to parse router lifetime, ignoring assignment: %s", rvalue);
+                return 0;
+        }
+        if (usec > 0) {
+                if (usec < RADV_MIN_ROUTER_LIFETIME_USEC) {
+                        log_syntax(unit, LOG_WARNING, filename, line, 0,
+                                   "Router lifetime %s is too short, using %s.",
+                                   FORMAT_TIMESPAN(usec, USEC_PER_SEC),
+                                   FORMAT_TIMESPAN(RADV_MIN_ROUTER_LIFETIME_USEC, USEC_PER_SEC));
+                        usec = RADV_MIN_ROUTER_LIFETIME_USEC;
+                } else if (usec > RADV_MAX_ROUTER_LIFETIME_USEC) {
+                        log_syntax(unit, LOG_WARNING, filename, line, 0,
+                                   "Router lifetime %s is too large, using %s.",
+                                   FORMAT_TIMESPAN(usec, USEC_PER_SEC),
+                                   FORMAT_TIMESPAN(RADV_MAX_ROUTER_LIFETIME_USEC, USEC_PER_SEC));
+                        usec = RADV_MAX_ROUTER_LIFETIME_USEC;
+                }
+        }
+
+        *lifetime = usec;
+        return 0;
+}
+
 int config_parse_router_preference(
                 const char *unit,
                 const char *filename,
diff --git a/src/network/networkd-radv.h b/src/network/networkd-radv.h
index 2d69a6fa27..392c00b37d 100644
--- a/src/network/networkd-radv.h
+++ b/src/network/networkd-radv.h
@@ -75,6 +75,7 @@ const char* radv_prefix_delegation_to_string(RADVPrefixDelegation i) _const_;
 RADVPrefixDelegation radv_prefix_delegation_from_string(const char *s) _pure_;
 
 CONFIG_PARSER_PROTOTYPE(config_parse_router_prefix_delegation);
+CONFIG_PARSER_PROTOTYPE(config_parse_router_lifetime);
 CONFIG_PARSER_PROTOTYPE(config_parse_router_preference);
 CONFIG_PARSER_PROTOTYPE(config_parse_prefix);
 CONFIG_PARSER_PROTOTYPE(config_parse_prefix_boolean);