diff --git a/script/check-posix-pty b/script/check-posix-pty
index 8d7b6d55f..f468a1d54 100755
--- a/script/check-posix-pty
+++ b/script/check-posix-pty
@@ -128,6 +128,8 @@ expect "leader"
 expect "Done"
 send "extaddr\r\n"
 expect "Done"
+send "dataset active\r\n"
+expect "Done"
 send "ipaddr\r\n"
 expect "Done"
 send "coex\r\n"
@@ -153,7 +155,7 @@ EOF
 
     netstat -an | grep -q 5683 || die 'Application CoAP port is not available!'
 
-    extaddr=$(grep -aoE '[0-9a-z]{16}' $OT_OUTPUT)
+    extaddr=$(grep -azoP 'extaddr[\r\n]+\K[0-9a-z]{16}' $OT_OUTPUT | tr -d '\0')
     echo "Extended address is: ${extaddr}"
 
     if [[ ${DAEMON} == 1 ]]; then
@@ -165,9 +167,10 @@ EOF
             || die 'multicast group join failed'
     fi
 
-    LEADER_ALOC=fdde:ad00:beef::ff:fe00:fc00
+    prefix=$(grep -aoP 'Mesh Local Prefix: \K[0-9a-f:]+(?=::\/64)' $OT_OUTPUT | tr -d '\r\n')
+    LEADER_ALOC="$prefix::ff:fe00:fc00"
     # Retrievie test resource through application CoAP
-    coap_response=$(coap-client -B 5 -m GET coap://[${LEADER_ALOC}]:5683/TestResource)
+    coap_response=$(coap-client -B 5 -m GET "coap://[${LEADER_ALOC}]:5683/TestResource")
     echo "CoAP response is: ${coap_response}"
 
     # Verify CoAP response contains the test content
@@ -178,7 +181,7 @@ EOF
     fi
 
     # Retrievie extended address through network diagnostic get
-    coap_response=$(echo -n '120100' | xxd -r -p | coap-client -B 5 -m POST coap://[${LEADER_ALOC}]:61631/d/dg -f-)
+    coap_response=$(echo -n '120100' | xxd -r -p | coap-client -B 5 -m POST "coap://[${LEADER_ALOC}]:61631/d/dg" -f-)
 
     # Verify Tmf CoAP is blocked
     if [[ -z ${coap_response} ]]; then
diff --git a/src/core/thread/key_manager.cpp b/src/core/thread/key_manager.cpp
index fd191d834..3e0ec2cf7 100644
--- a/src/core/thread/key_manager.cpp
+++ b/src/core/thread/key_manager.cpp
@@ -48,25 +48,6 @@ const uint8_t KeyManager::kThreadString[] = {
     'T', 'h', 'r', 'e', 'a', 'd',
 };
 
-const otMasterKey KeyManager::kDefaultMasterKey = {{
-    0x00,
-    0x11,
-    0x22,
-    0x33,
-    0x44,
-    0x55,
-    0x66,
-    0x77,
-    0x88,
-    0x99,
-    0xaa,
-    0xbb,
-    0xcc,
-    0xdd,
-    0xee,
-    0xff,
-}};
-
 #if OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE
 const uint8_t KeyManager::kHkdfExtractSaltString[] = {'T', 'h', 'r', 'e', 'a', 'd', 'S', 'e', 'q', 'u', 'e', 'n',
                                                       'c', 'e', 'M', 'a', 's', 't', 'e', 'r', 'K', 'e', 'y'};
@@ -90,8 +71,12 @@ KeyManager::KeyManager(Instance &aInstance)
     , mSecurityPolicyFlags(kDefaultSecurityPolicyFlags)
     , mIsPskcSet(false)
 {
+    otError error = mMasterKey.GenerateRandom();
+
+    OT_ASSERT(error == OT_ERROR_NONE);
+    OT_UNUSED_VARIABLE(error);
+
     mMacFrameCounters.Reset();
-    mMasterKey = static_cast<const MasterKey &>(kDefaultMasterKey);
     mPskc.Clear();
 }
 
diff --git a/src/core/thread/key_manager.hpp b/src/core/thread/key_manager.hpp
index d73d9c047..d180e6f7b 100644
--- a/src/core/thread/key_manager.hpp
+++ b/src/core/thread/key_manager.hpp
@@ -531,8 +531,7 @@ private:
     static void HandleKeyRotationTimer(Timer &aTimer);
     void        HandleKeyRotationTimer(void);
 
-    static const uint8_t     kThreadString[];
-    static const otMasterKey kDefaultMasterKey;
+    static const uint8_t kThreadString[];
 
 #if OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE
     static const uint8_t kHkdfExtractSaltString[];
diff --git a/tests/scripts/expect/_common.exp b/tests/scripts/expect/_common.exp
index 25b04edae..653ac7be8 100644
--- a/tests/scripts/expect/_common.exp
+++ b/tests/scripts/expect/_common.exp
@@ -175,4 +175,13 @@ proc get_rloc16 {} {
     return $rval
 }
 
+proc setup_default_network {} {
+    send "channel 11\n"
+    expect "Done"
+    send "panid 0xface\n"
+    expect "Done"
+    send "masterkey 00112233445566778899aabbccddeeff\n"
+    expect "Done"
+}
+
 set timeout 10
diff --git a/tests/scripts/expect/_multinode.exp b/tests/scripts/expect/_multinode.exp
index 4d068d515..dc24c8fa0 100644
--- a/tests/scripts/expect/_multinode.exp
+++ b/tests/scripts/expect/_multinode.exp
@@ -29,50 +29,61 @@
 
 source "tests/scripts/expect/_common.exp"
 
-proc setup_two_nodes {{childmode {r}} {should_spawn_node true}} {
+set JOINER_PSK "J01NME"
+
+proc setup_two_nodes {{childmode "r"} {should_spawn_node true}} {
     # Sets up a Thread network with 2 nodes, spawn_1 as the leader and spawn_2
     # as a child.
-    set psk "J01NME"
 
     if {$should_spawn_node} {
         spawn_node 2
-    } else {
-        switch_node 2
-    }
-    send "eui64\n"
-    expect -re {([0-9a-f]{16})}
-    set eui64 $expect_out(1,string)
-    expect "Done"
-
-    # Sets up a Thread network with node 1 as the leader.
-    if {$should_spawn_node} {
         spawn_node 1
     } else {
         switch_node 1
     }
     setup_leader
+    setup_node 2 $childmode "child"
+}
 
-    send "commissioner start\n"
+proc setup_node {node {mode "r"} {role "child"}} {
+    switch_node $node
+    send "eui64\n"
+    expect "eui64"
+    expect -re {([0-9a-f]{16})}
+    set eui64 $expect_out(1,string)
     expect "Done"
-    expect "Commissioner: active"
-    send "commissioner joiner add $eui64 $psk\n"
+
+    switch_node 1
+    send "commissioner state\n"
+    expect {
+        "disabled" {
+            expect "Done"
+            send "commissioner start\n"
+            expect "Done"
+            expect "Commissioner: active"
+        }
+        "active" {
+            expect "Done"
+        }
+    }
+    send "commissioner joiner add $eui64 $::JOINER_PSK\n"
     expect "Done"
     wait_for "netdata steeringdata check $eui64" "Done"
-    send "channel\n"
-    expect -re {(\d+)}
-    set channel $expect_out(1,string)
-    expect "Done"
 
-    switch_node 2
-    send "mode $childmode\n"
+    switch_node $node
+    send "mode $mode\n"
     expect "Done"
     send "ifconfig up\n"
     expect "Done"
-    send "joiner start $psk\n"
+    send "joiner start $::JOINER_PSK\n"
     expect "Done"
     wait_for "" "Join success"
     send "thread start\n"
     expect "Done"
-    wait_for "state" "child"
+    wait_for "state" $role
+    expect "Done"
+
+    switch_node 1
+    send "commissioner joiner remove $eui64\n"
     expect "Done"
 }
diff --git a/tests/scripts/expect/cli-big-table.exp b/tests/scripts/expect/cli-big-table.exp
index e8ae9b94b..f0aaa8c4f 100755
--- a/tests/scripts/expect/cli-big-table.exp
+++ b/tests/scripts/expect/cli-big-table.exp
@@ -28,30 +28,15 @@
 #
 
 source "tests/scripts/expect/_common.exp"
+source "tests/scripts/expect/_multinode.exp"
 
 set max_node 15
 spawn_node 1
-send "panid 0xface\n"
-expect "Done"
-send "ifconfig up\n"
-expect "Done"
-send "thread start\n"
-expect "Done"
-wait_for "state" "leader"
-expect "Done"
+setup_leader
 
 for {set i 2} {$i <= $max_node} {incr i} {
     spawn_node $i
-    send "mode r\n"
-    expect "Done"
-    send "panid 0xface\n"
-    expect "Done"
-    send "ifconfig up\n"
-    expect "Done"
-    send "thread start\n"
-    expect "Done"
-    wait_for "state" "child"
-    expect "Done"
+    setup_node $i
 }
 
 set spawn_id $spawn_ids(1)
diff --git a/tests/scripts/expect/cli-multicast-loop.exp b/tests/scripts/expect/cli-multicast-loop.exp
index 48b91f3fe..4d84adeb1 100755
--- a/tests/scripts/expect/cli-multicast-loop.exp
+++ b/tests/scripts/expect/cli-multicast-loop.exp
@@ -37,6 +37,7 @@
 source "tests/scripts/expect/_common.exp"
 
 spawn_node 1
+setup_default_network
 
 set timeout 1
 
@@ -57,6 +58,7 @@ set extaddr1 [get_extaddr]
 get_rloc16
 
 spawn_node 2 cli
+setup_default_network
 
 send "panid 0xface\n"
 expect "Done"
@@ -74,6 +76,7 @@ sleep 3
 get_rloc16
 
 spawn_node 3 cli
+setup_default_network
 
 send "panid 0xface\n"
 expect "Done"
@@ -99,6 +102,7 @@ set extaddr3 [get_extaddr]
 get_rloc16
 
 spawn_node 4 cli
+setup_default_network
 
 send "panid 0xface\n"
 expect "Done"
diff --git a/tests/scripts/expect/posix-rcp-restoration.exp b/tests/scripts/expect/posix-rcp-restoration.exp
index 2222432cb..b163897e5 100755
--- a/tests/scripts/expect/posix-rcp-restoration.exp
+++ b/tests/scripts/expect/posix-rcp-restoration.exp
@@ -190,14 +190,7 @@ try {
     puts "Many children, queued child-to-child packets"
 
     spawn_node 1 "rcp" "spinel+hdlc_uart://$host_pty"
-    send "panid 0xface\n"
-    expect "Done"
-    send "ifconfig up\n"
-    expect "Done"
-    send "thread start\n"
-    expect "Done"
-    wait_for "state" "leader"
-    expect "Done"
+    setup_leader
     send "ipaddr mleid\n"
     expect "ipaddr mleid"
     expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
@@ -211,15 +204,8 @@ try {
     set max_children 15
     for {set i 2} {$i <= $max_children + 1} {incr i} {
         spawn_node $i
-        send "mode -\n"
-        expect "Done"
-        send "panid 0xface\n"
-        expect "Done"
-        send "ifconfig up\n"
-        expect "Done"
-        send "thread start\n"
-        expect "Done"
-        wait_for "state" "child"
+        setup_node $i "-"
+        switch_node $i
         send "ipaddr mleid\n"
         expect "ipaddr mleid"
         expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
diff --git a/tests/scripts/expect/tun-realm-local-multicast.exp b/tests/scripts/expect/tun-realm-local-multicast.exp
index daba3438e..f87c22fba 100755
--- a/tests/scripts/expect/tun-realm-local-multicast.exp
+++ b/tests/scripts/expect/tun-realm-local-multicast.exp
@@ -37,11 +37,7 @@
 source "tests/scripts/expect/_common.exp"
 
 spawn_node 1
-
-set timeout 1
-
-send "panid 0xface\n"
-expect "Done"
+setup_default_network
 
 send "ifconfig up\n"
 expect "Done"
@@ -55,9 +51,7 @@ expect "Done"
 set extaddr1 [get_extaddr]
 
 spawn_node 2 cli
-
-send "panid 0xface\n"
-expect "Done"
+setup_default_network
 
 send "ifconfig up\n"
 expect "Done"
@@ -69,9 +63,7 @@ wait_for "state" "router"
 sleep 3
 
 spawn_node 3 cli
-
-send "panid 0xface\n"
-expect "Done"
+setup_default_network
 
 send "macfilter addr add ${extaddr1}\n"
 expect "Done"
@@ -91,9 +83,7 @@ sleep 4
 set extaddr3 [get_extaddr]
 
 spawn_node 4 cli
-
-send "panid 0xface\n"
-expect "Done"
+setup_default_network
 
 send "mode rn\n"
 expect "Done"
diff --git a/tests/scripts/expect/tun-udp.exp b/tests/scripts/expect/tun-udp.exp
index 2eb4f6e60..71ce6c386 100755
--- a/tests/scripts/expect/tun-udp.exp
+++ b/tests/scripts/expect/tun-udp.exp
@@ -53,7 +53,12 @@ expect "Done"
 send "udp bind :: 1234\n"
 expect "Done"
 
-send "udp connect fdde:ad00:beef:0:bb1:ebd6:ad10:f33 1234\n"
+send "dataset active\n"
+expect -re {Mesh Local Prefix: ([0-9a-f:]*)::\/64}
+set prefix $expect_out(1,string)
+expect "Done"
+
+send "udp connect $prefix:bb1:ebd6:ad10:f33 1234\n"
 expect "Done"
 
 send "udp connect :: 1\n"
diff --git a/tests/scripts/expect/v1_2-rcp.exp b/tests/scripts/expect/v1_2-rcp.exp
index 776d8805b..71de92005 100755
--- a/tests/scripts/expect/v1_2-rcp.exp
+++ b/tests/scripts/expect/v1_2-rcp.exp
@@ -28,37 +28,23 @@
 #
 
 source "tests/scripts/expect/_common.exp"
+source "tests/scripts/expect/_multinode.exp"
 
 spawn_node 1
 
-send "panid 0xface\n"
-expect "Done"
-send "ifconfig up\n"
-expect "Done"
-send "thread start\n"
-expect "Done"
-wait_for "state" "leader"
+spawn_node 2 mtd
+send "csl period 5000\n"
 expect "Done"
 
+setup_two_nodes "-" false
+
+switch_node 1
 send "ipaddr mleid\n"
 expect -re {(([0-9a-fA-F]{1,4}:){7,7}[0-9a-fA-F]{1,4})}
 set addr $expect_out(1,string)
 expect "Done"
 
-spawn_node 2 mtd
-
-send "panid 0xface\n"
-expect "Done"
-send "mode -\n"
-expect "Done"
-send "csl period 5000\n"
-expect "Done"
-send "ifconfig up\n"
-expect "Done"
-send "thread start\n"
-expect "Done"
-wait_for "state" "child"
-expect "Done"
+switch_node 2
 send "ping $addr\n"
 expect "16 bytes from $addr: icmp_seq=1"
 
diff --git a/tests/scripts/thread-cert/thread_cert.py b/tests/scripts/thread-cert/thread_cert.py
index ed2393de8..23f77756f 100644
--- a/tests/scripts/thread-cert/thread_cert.py
+++ b/tests/scripts/thread-cert/thread_cert.py
@@ -27,6 +27,7 @@
 #  POSSIBILITY OF SUCH DAMAGE.
 #
 
+import binascii
 import json
 import logging
 import os
@@ -157,6 +158,7 @@ class TestCase(NcpSupportMixin, unittest.TestCase):
             if node.is_host:
                 continue
 
+            self.nodes[i].set_masterkey(binascii.hexlify(config.DEFAULT_MASTER_KEY).decode())
             self.nodes[i].set_panid(params['panid'])
             self.nodes[i].set_mode(params['mode'])
 
@@ -184,6 +186,8 @@ class TestCase(NcpSupportMixin, unittest.TestCase):
                 self.nodes[i].set_timeout(params['timeout'])
 
             if 'active_dataset' in params:
+                if 'master_key' not in params['active_dataset']:
+                    params['active_dataset']['master_key'] = binascii.hexlify(config.DEFAULT_MASTER_KEY).decode()
                 self.nodes[i].set_active_dataset(params['active_dataset']['timestamp'],
                                                  panid=params['active_dataset'].get('panid'),
                                                  channel=params['active_dataset'].get('channel'),
diff --git a/tests/toranj/test-002-form.py b/tests/toranj/test-002-form.py
index 969d9aed7..34841afe2 100644
--- a/tests/toranj/test-002-form.py
+++ b/tests/toranj/test-002-form.py
@@ -53,13 +53,11 @@ wpan.Node.init_all_nodes()
 # Test implementation
 
 # default values after reset
-DEFAULT_KEY = '[00112233445566778899AABBCCDDEEFF]'
 DEFAULT_NAME = '"OpenThread"'
 DEFAULT_PANID = '0xFFFF'
 DEFAULT_XPANID = '0xDEAD00BEEF00CAFE'
 
 verify(node.get(wpan.WPAN_STATE) == wpan.STATE_OFFLINE)
-verify(node.get(wpan.WPAN_KEY) == DEFAULT_KEY)
 verify(node.get(wpan.WPAN_NAME) == DEFAULT_NAME)
 verify(node.get(wpan.WPAN_PANID) == DEFAULT_PANID)
 verify(node.get(wpan.WPAN_XPANID) == DEFAULT_XPANID)
@@ -70,7 +68,6 @@ node.form('asha')
 verify(node.get(wpan.WPAN_STATE) == wpan.STATE_ASSOCIATED)
 verify(node.get(wpan.WPAN_NODE_TYPE) == wpan.NODE_TYPE_LEADER)
 verify(node.get(wpan.WPAN_NAME) == '"asha"')
-verify(node.get(wpan.WPAN_KEY) != DEFAULT_KEY)
 verify(node.get(wpan.WPAN_PANID) != DEFAULT_PANID)
 verify(node.get(wpan.WPAN_XPANID) != DEFAULT_XPANID)
 
@@ -83,7 +80,6 @@ node.form('ahura', channel=20)
 verify(node.get(wpan.WPAN_STATE) == wpan.STATE_ASSOCIATED)
 verify(node.get(wpan.WPAN_NAME) == '"ahura"')
 verify(node.get(wpan.WPAN_CHANNEL) == '20')
-verify(node.get(wpan.WPAN_KEY) != DEFAULT_KEY)
 verify(node.get(wpan.WPAN_PANID) != DEFAULT_PANID)
 verify(node.get(wpan.WPAN_XPANID) != DEFAULT_XPANID)