diff --git a/tests/forge.py b/tests/forge.py
index 06514d8647d10fb3b1bb839cfa887382cf664215..edd956a40dd8ee8d6bab54c90d0c2f919a7d23bf 100644
--- a/tests/forge.py
+++ b/tests/forge.py
@@ -22,20 +22,23 @@ import optparse
 import os
 import sys
 import threading
+import fcntl
+import socket
+import struct
+import sys
 
 
-from init_all import SOFTWARE_INSTALL_PATH, LOGLEVEL, PROTO, SOFTWARE_UNDER_TEST, DB_TYPE, SHOW_PACKETS_FROM, \
+from init_all import SOFTWARE_INSTALL_PATH, LOGLEVEL, SOFTWARE_UNDER_TEST, DB_TYPE, SHOW_PACKETS_FROM, \
     SRV4_ADDR, REL4_ADDR, GIADDR4, IFACE, CLI_LINK_LOCAL, SERVER_IFACE, OUTPUT_WAIT_INTERVAL, \
     OUTPUT_WAIT_MAX_INTERVALS, PACKET_WAIT_INTERVAL, SRV_IPV6_ADDR_GLOBAL, SRV_IPV6_ADDR_LINK_LOCAL, HISTORY,\
     TCPDUMP, TCPDUMP_PATH, SAVE_CONFIG_FILE, AUTO_ARCHIVE, SLEEP_TIME_1, SLEEP_TIME_2, MGMT_ADDRESS, MGMT_USERNAME,\
-    MGMT_PASSWORD, SAVE_LOGS, BIND_LOG_TYPE, BIND_LOG_LVL, BIND_MODULE, SAVE_LEASES, DNS_IFACE, DNS_ADDR, DNS_PORT, \
+    MGMT_PASSWORD, SAVE_LOGS, BIND_LOG_TYPE, BIND_LOG_LVL, BIND_MODULE, SAVE_LEASES, DNS_IFACE, DNS4_ADDR, DNS6_ADDR, DNS_PORT, \
     DNS_SERVER_INSTALL_PATH, DNS_DATA_PATH, ISC_DHCP_LOG_FACILITY, ISC_DHCP_LOG_FILE, DB_NAME, DB_USER, DB_PASSWD,\
     DB_HOST, CIADDR, MGMT_ADDRESS_2, MGMT_ADDRESS_3
 
 # Create Forge configuration class
 SOFTWARE_INSTALL_DIR = SOFTWARE_INSTALL_PATH  # for backward compatibility of tests
 LOGLEVEL = os.getenv('LOGLEVEL', LOGLEVEL)
-PROTO = os.getenv('PROTO', PROTO)
 SOFTWARE_UNDER_TEST = os.getenv('SOFTWARE_UNDER_TEST', SOFTWARE_UNDER_TEST)
 DB_TYPE = os.getenv('DB_TYPE', DB_TYPE)
 SOFTWARE_INSTALL_PATH = os.getenv('SOFTWARE_INSTALL_DIR', SOFTWARE_INSTALL_PATH)
@@ -70,7 +73,8 @@ BIND_LOG_LVL = os.getenv('BIND_LOG_LVL', BIND_LOG_LVL)
 BIND_MODULE = os.getenv('BIND_MODULE', BIND_MODULE)
 SAVE_LEASES = os.getenv('SAVE_LEASES', SAVE_LEASES)
 DNS_IFACE = os.getenv('DNS_IFACE', DNS_IFACE)
-DNS_ADDR = os.getenv('DNS_ADDR', DNS_ADDR)
+DNS4_ADDR = os.getenv('DNS4_ADDR', DNS4_ADDR)
+DNS6_ADDR = os.getenv('DNS6_ADDR', DNS6_ADDR)
 DNS_PORT = os.getenv('DNS_PORT', DNS_PORT)
 DNS_SERVER_INSTALL_PATH = os.getenv('DNS_SERVER_INSTALL_PATH', DNS_SERVER_INSTALL_PATH)
 DNS_DATA_PATH = os.getenv('DNS_DATA_PATH', DNS_DATA_PATH)
@@ -116,7 +120,7 @@ class ForgeConfiguration:
         self.packet_wait_interval = PACKET_WAIT_INTERVAL
 
         # DHCP
-        self.proto = PROTO
+        self.proto = 'v4'  # default value but it is overriden by each test in terrain.declare_all()
         self.software_under_test = SOFTWARE_UNDER_TEST
         self.software_install_path = SOFTWARE_INSTALL_PATH
         self.software_install_dir = SOFTWARE_INSTALL_PATH  # that keeps backwards compatibility
@@ -141,7 +145,8 @@ class ForgeConfiguration:
 
         # DNS
         self.dns_iface = DNS_IFACE
-        self.dns_addr = DNS_ADDR
+        self.dns4_addr = DNS4_ADDR
+        self.dns6_addr = DNS6_ADDR
         self.dns_port = DNS_PORT
         self.dns_data_path = DNS_DATA_PATH
         self.dns_server_install_path = DNS_SERVER_INSTALL_PATH
@@ -162,7 +167,6 @@ class ForgeConfiguration:
         self.basic_validation()
 
     def gethwaddr(self, ifname):
-        import fcntl, socket, struct, sys
         if sys.platform != "darwin":
             s = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
             info = fcntl.ioctl(s.fileno(), 0x8927,  struct.pack('256s', ifname))
@@ -172,26 +176,21 @@ class ForgeConfiguration:
             return "0a:00:27:00:00:00"
 
     def basic_validation(self):
-        from sys import exit
-        if self.proto not in ["v4", "v6"]:
-            print "Configuration failure, protocol version not set properly." \
-                  " Please use ./forge.py -T to validate configuration."
-            exit(-1)
         if self.proto == "v4" and self.software_under_test[0] not in ["none_server"]:
             if "4" not in self.software_under_test[0]:
                 print "Miss match of protocol version and DHCP server version"
-                exit(-1)
+                sys.exit(-1)
         if self.proto == "v6" and self.software_under_test[0] not in ["none_server"]:
             if "6" not in self.software_under_test[0]:
                 print "Miss match of protocol version and DHCP server version"
-                exit(-1)
+                sys.exit(-1)
         if self.software_install_path == "":
             print "Configuration failure, software_install_path empty." \
                   " Please use ./forge.py -T to validate configuration."
-            exit(-1)
+            sys.exit(-1)
         if self.mgmt_address == "":
             print "Configuration failure, mgmt_address empty. Please use ./forge.py -T to validate configuration."
-            exit(-1)
+            sys.exit(-1)
 
     def set_env_val(self, env_name, env_val):
         """
diff --git a/tests/init_all.py_default b/tests/init_all.py_default
index fc6d2b3cc1d0839db2e5f5a7ec02663e061cb505..b117bfbacb5c87beb9d57bc1927ecff601bd8f04 100644
--- a/tests/init_all.py_default
+++ b/tests/init_all.py_default
@@ -43,10 +43,6 @@ SOFTWARE_UNDER_TEST = "",
 # INCORRECT COMBINATIONS: SOFTWARE_UNDER_TEST = "kea6_server","kea4_server"
 # or SOFTWARE_UNDER_TEST = "kea6_server","dibbler_client"
 
-# This defines protocol family. Currently two are
-# supported: v4 (which means DHCPv4) and v6 (which means DHCPv6)
-PROTO = ""
-
 # Parameters specific to DHCPv4 tests
 SRV4_ADDR = ""
 
@@ -212,7 +208,8 @@ ISC_DHCP_LOG_FILE = "/var/log/forge_dhcpd.log"
 DNS_IFACE = ""
 
 # DNS server address:
-DNS_ADDR = ""
+DNS4_ADDR = ""
+DNS6_ADDR = ""
 
 # DNS port number, default value is 53
 DNS_PORT = 53
diff --git a/tests/init_all.py_example b/tests/init_all.py_example
index dccb75220a84ec4fcef683bb8a4a74476b63128a..49fbb846094a2d9a83c2e4c7f3649e6d46f43a8c 100644
--- a/tests/init_all.py_example
+++ b/tests/init_all.py_example
@@ -43,10 +43,6 @@ SOFTWARE_UNDER_TEST = "kea6_server",
 # INCORRECT COMBINATIONS: SOFTWARE_UNDER_TEST = "kea6_server","kea4_server"
 # or SOFTWARE_UNDER_TEST = "kea6_server","dibbler_client"
 
-# This defines protocol family. Currently two are
-# supported: v4 (which means DHCPv4) and v6 (which means DHCPv6)
-PROTO = "v6"
-
 # Parameters specific to DHCPv4 tests
 SRV4_ADDR = ""
 
@@ -212,7 +208,8 @@ ISC_DHCP_LOG_FILE = "/var/log/forge_dhcpd.log"
 DNS_IFACE = ""
 
 # DNS server address:
-DNS_ADDR = ""
+DNS4_ADDR = ""
+DNS6_ADDR = ""
 
 # DNS port number, default value is 53
 DNS_PORT = 53
@@ -221,4 +218,4 @@ DNS_PORT = 53
 DNS_SERVER_INSTALL_DIR = ""
 
 # Additional path for server management:
-DNS_DATA_DIR = ""
\ No newline at end of file
+DNS_DATA_DIR = ""
diff --git a/tests/protosupport/dns.py b/tests/protosupport/dns.py
index 5e6203b586b86772ff86b9e32155af7a8f79d78a..f5370968c37c3aa8d5786794c1471516547ca1ef 100644
--- a/tests/protosupport/dns.py
+++ b/tests/protosupport/dns.py
@@ -166,9 +166,9 @@ def dns_question_record(addr, my_qtype, my_qclass):
 
 def build_msg():
     if world.proto == "v6":
-        msg = IPv6(dst=world.cfg["dns_addr"])/UDP(sport=world.cfg["dns_port"], dport=world.cfg["dns_port"])
+        msg = IPv6(dst=world.cfg["dns6_addr"])/UDP(sport=world.cfg["dns_port"], dport=world.cfg["dns_port"])
     else:
-        msg = IP(dst=world.cfg["dns_addr"])/UDP(sport=world.cfg["dns_port"], dport=world.cfg["dns_port"])
+        msg = IP(dst=world.cfg["dns4_addr"])/UDP(sport=world.cfg["dns_port"], dport=world.cfg["dns_port"])
     msg.trid = random.randint(0, 256*256*256)
     world.climsg.append(msg/world.dns_query)
 
diff --git a/tests/protosupport/multi_protocol_functions.py b/tests/protosupport/multi_protocol_functions.py
index 58d81b503dace4914ba9a48a6ef2f1eb376ec449..7bba2bf55ac3d3781a75655f6b401a52e15b7c67 100644
--- a/tests/protosupport/multi_protocol_functions.py
+++ b/tests/protosupport/multi_protocol_functions.py
@@ -289,12 +289,6 @@ def change_network_variables(value_name, value):
         # world.cfg["address_v6"] = value
     elif value_name == "destination_address":
         world.cfg["destination_IP"] = value
-    elif value_name == "dns_iface":
-        world.cfg["dns_iface"] = value
-    elif value_name == "dns_address":
-        world.cfg["dns_addr"] = value
-    elif value_name == "dns_port":
-        world.cfg["dns_port"] = int(value)
     else:
         assert False, "There is no possibility of configuration value named: {value_name}".format(**locals())
 
diff --git a/tests/softwaresupport/bind9_server/functions.py b/tests/softwaresupport/bind9_server/functions.py
index d3c18f0a559367ac429d0fcd2241b91b5f0bc591..287ad6d4525115b278df6a27e0a222b7dd6aed20 100644
--- a/tests/softwaresupport/bind9_server/functions.py
+++ b/tests/softwaresupport/bind9_server/functions.py
@@ -94,8 +94,12 @@ def add_rndc(address, port, alg, value):
 
 def _patch_config(cfg):
     tpl = string.Template(cfg)
+    if world.f_cfg.proto == 'v4':
+        dns_addr = world.f_cfg.dns4_addr
+    else:
+        dns_addr = world.f_cfg.dns6_addr
     return tpl.safe_substitute(data_path=os.path.join(world.f_cfg.dns_data_path, 'namedb'),
-                               dns_addr=world.f_cfg.dns_addr,
+                               dns_addr=dns_addr,
                                dns_port=world.f_cfg.dns_port)
 
 
diff --git a/tests/srv_control.py b/tests/srv_control.py
index 6df96a926e7e69e0f9d748501ae13757dc314cce..7ed44ad6de85f78afbbf788e654f9a3e18e2d4a5 100644
--- a/tests/srv_control.py
+++ b/tests/srv_control.py
@@ -991,12 +991,20 @@ def add_ddns_server_options(option, value):
 
 @step('Add forward DDNS with name (\S+) and key (\S+) on address (\S+) and port (\S+).')
 def add_forward_ddns(name, key_name):
-    ddns.add_forward_ddns(name, key_name, world.f_cfg.dns_addr, world.f_cfg.dns_port)
+    if world.f_cfg.proto == 'v4':
+        ip_address = world.f_cfg.dns4_addr
+    else:
+        ip_address = world.f_cfg.dns6_addr
+    ddns.add_forward_ddns(name, key_name, ip_address, world.f_cfg.dns_port)
 
 
 @step('Add reverse DDNS with name (\S+) and key (\S+) on address (\S+) and port (\S+).')
 def add_reverse_ddns(name, key_name):
-    ddns.add_reverse_ddns(name, key_name, world.f_cfg.dns_addr, world.f_cfg.dns_port)
+    if world.f_cfg.proto == 'v4':
+        ip_address = world.f_cfg.dns4_addr
+    else:
+        ip_address = world.f_cfg.dns6_addr
+    ddns.add_reverse_ddns(name, key_name, ip_address, world.f_cfg.dns_port)
 
 
 @step('Add DDNS key named (\S+) based on (\S+) with secret value (\S+).')
diff --git a/tests/srv_msg.py b/tests/srv_msg.py
index 5b6fe75bdd7099fd9a630e8d538c78cdc530efa6..3dd56c8052168f0e7fba19992430ab8d497ec1dd 100644
--- a/tests/srv_msg.py
+++ b/tests/srv_msg.py
@@ -257,19 +257,6 @@ def client_send_dns_query():
     dns.send_query()
 
 
-@step('Through (\S+) interface client sends DNS query.')
-def client_send_dns_query_interface(iface):
-    world.cfg["dns_iface"] = iface
-    dns.send_query()
-
-
-@step('Through (\S+) interface to address (\S+) client sends DNS query.')
-def client_send_dns_query_interface_address(iface, addr):
-    world.cfg["dns_iface"] = iface
-    world.cfg["dns_addr"] = addr
-    dns.send_query()
-
-
 ##checking DNS respond
 @step('DNS server (\S+) (NOT )?respond with DNS query.')
 def send_wait_for_query(type, yes_or_no):
diff --git a/tests/terrain.py b/tests/terrain.py
index 7c1335639cdbdf74634f30aa86d8fc69df1fa31d..4842dc3b8dd75df0ab1ad3dad37f6242ce8b6a62 100644
--- a/tests/terrain.py
+++ b/tests/terrain.py
@@ -194,7 +194,8 @@ def _v6_initialize():
 
 def _dns_initialize():
     world.cfg["dns_iface"] = world.f_cfg.dns_iface
-    world.cfg["dns_addr"] = world.f_cfg.dns_addr
+    world.cfg["dns4_addr"] = world.f_cfg.dns4_addr
+    world.cfg["dns6_addr"] = world.f_cfg.dns6_addr
     world.cfg["dns_port"] = world.f_cfg.dns_port
     world.dns_enable = True