diff --git a/smoketest/scripts/cli/test_firewall.py b/smoketest/scripts/cli/test_firewall.py
index d8f29d4d512..d05e4e17c0d 100755
--- a/smoketest/scripts/cli/test_firewall.py
+++ b/smoketest/scripts/cli/test_firewall.py
@@ -328,8 +328,6 @@ def test_ipv4_time_weekdays(self):
 
     def test_ipv4_advanced(self):
         name = 'smoketest-adv'
-        name2 = 'smoketest-adv2'
-        interface = 'eth0'
 
         self.cli_set(['firewall', 'ipv4', 'name', name, 'default-action', 'drop'])
         self.cli_set(['firewall', 'ipv4', 'name', name, 'default-log'])
@@ -415,7 +413,6 @@ def test_ipv4_synproxy(self):
 
     def test_ipv4_mask(self):
         name = 'smoketest-mask'
-        interface = 'eth0'
 
         self.cli_set(['firewall', 'group', 'address-group', 'mask_group', 'address', '1.1.1.1'])
 
@@ -644,7 +641,6 @@ def test_ipv6_advanced(self):
 
     def test_ipv6_mask(self):
         name = 'v6-smoketest-mask'
-        interface = 'eth0'
 
         self.cli_set(['firewall', 'group', 'ipv6-address-group', 'mask_group', 'address', '::beef'])
 
diff --git a/src/conf_mode/firewall.py b/src/conf_mode/firewall.py
index eacded5ef81..3a98c2a8bbd 100755
--- a/src/conf_mode/firewall.py
+++ b/src/conf_mode/firewall.py
@@ -569,7 +569,9 @@ def verify(firewall):
                             if 'jump' not in priority_conf['default_action']:
                                 raise ConfigError('default-jump-target defined, but default-action jump needed and it is not defined')
                             if priority_conf['default_jump_target'] == priority:
-                                raise ConfigError(f'Loop detected on default-jump-target.')
+                                raise ConfigError(
+                                    'Loop detected on default-jump-target.'
+                                )
                             if target not in dict_search_args(firewall[family], 'name'):
                                 raise ConfigError(f'Invalid jump-target. Firewall name {target} does not exist on the system')
                         if 'rule' in priority_conf:
@@ -605,7 +607,9 @@ def verify(firewall):
                     for iface in zone_conf['member']['interface']:
 
                         if iface in zone_interfaces:
-                            raise ConfigError(f'Interfaces cannot be assigned to multiple zones')
+                            raise ConfigError(
+                                'Interfaces cannot be assigned to multiple zones'
+                            )
 
                         iface_vrf = get_interface_vrf(iface)
                         if iface_vrf != 'default':
@@ -615,7 +619,9 @@ def verify(firewall):
                 if 'vrf' in zone_conf['member']:
                     for vrf in zone_conf['member']['vrf']:
                         if vrf in zone_vrf:
-                            raise ConfigError(f'VRF cannot be assigned to multiple zones')
+                            raise ConfigError(
+                                'VRF cannot be assigned to multiple zones'
+                            )
                         zone_vrf.append(vrf)
 
             if 'vrf_interfaces' in zone_conf:
@@ -750,7 +756,7 @@ def apply(firewall):
     ## DOMAIN RESOLVER
     domain_action = 'restart'
     if dict_search_args(firewall, 'group', 'remote_group') or dict_search_args(firewall, 'group', 'domain_group') or firewall['ip_fqdn'].items() or firewall['ip6_fqdn'].items():
-        text = f'# Automatically generated by firewall.py\nThis file indicates that vyos-domain-resolver service is used by the firewall.\n'
+        text = '# Automatically generated by firewall.py\nThis file indicates that vyos-domain-resolver service is used by the firewall.\n'
         write_file(domain_resolver_usage, text)
     else:
         if os.path.exists(domain_resolver_usage):
diff --git a/src/op_mode/firewall.py b/src/op_mode/firewall.py
index 962eff63987..0d58ba3c750 100755
--- a/src/op_mode/firewall.py
+++ b/src/op_mode/firewall.py
@@ -74,7 +74,7 @@ def get_nftables_details(family, hook, priority):
 
     try:
         results = cmdl(command)
-    except:
+    except (OSError, UnicodeDecodeError):
         return {}
 
     out = {}
@@ -112,7 +112,7 @@ def get_nftables_state_details(family):
     command = ['nft', 'list', 'chain', suffix, 'vyos_filter', f'VYOS_STATE_{name_suffix}']
     try:
         results = cmdl(command)
-    except:
+    except (OSError, UnicodeDecodeError):
         return {}
 
     out = {}
@@ -135,7 +135,7 @@ def get_nftables_group_members(family, table, name):
     try:
         results_str = cmdl(['nft', '-j', 'list', 'set', prefix, table, name])
         results = json.loads(results_str)
-    except:
+    except (OSError, UnicodeDecodeError, json.JSONDecodeError):
         return out
 
     if 'nftables' not in results:
@@ -163,7 +163,7 @@ def get_nftables_remote_group_members(family, table, name):
     try:
         results_str = cmdl(['nft', '-j', 'list', 'set', prefix, table, name])
         results = json.loads(results_str)
-    except:
+    except (OSError, UnicodeDecodeError, json.JSONDecodeError):
         return out
 
     if 'nftables' not in results: