diff --git a/app.py b/app.py
index 3de273d..d208004 100644
--- a/app.py
+++ b/app.py
@@ -436,6 +436,7 @@ def api_diagnose_start():
         if pd.get('port_idx') == port_idx:
             port_data = dict(pd)
             port_data['name'] = pname
+            port_data['switch_name'] = switch_name
             break
     if not port_data:
         return jsonify({'error': f'Port {port_idx} not found on switch "{switch_name}"'}), 404
diff --git a/diagnose.py b/diagnose.py
index e7ec513..b6e4300 100644
--- a/diagnose.py
+++ b/diagnose.py
@@ -530,15 +530,16 @@ class DiagnosticsRunner:
             add(warnings, 'KERNEL_EVENTS',
                 f'{len(err_events)} recent kernel error event(s) for this interface in dmesg')
 
-        # LLDP validation
+        # LLDP validation: the neighbour the *server's* lldpd sees should be the switch
+        # that this port belongs to. (The switch port's own LLDP entry describes the server,
+        # so it must not be compared with the server's view of the switch.)
         if lldp.get('available'):
-            sw_lldp = switch_port_data.get('lldp') or {}
-            sw_system = (sw_lldp.get('system_name') or '').lower()
+            expected_switch = (switch_port_data.get('switch_name') or '').lower()
             srv_neighbor = (lldp.get('neighbor_system') or '').lower()
-            if sw_system and srv_neighbor and sw_system not in srv_neighbor and srv_neighbor not in sw_system:
+            if expected_switch and srv_neighbor and expected_switch not in srv_neighbor and srv_neighbor not in expected_switch:
                 add(warnings, 'LLDP_MISMATCH',
-                    f'LLDP mismatch: switch sees "{sw_lldp.get("system_name")}" but '
-                    f'server lldpctl sees "{lldp.get("neighbor_system")}" — cross-cabled port?')
+                    f'LLDP mismatch: this port is on "{switch_port_data.get("switch_name")}" but the server\'s '
+                    f'lldpctl sees "{lldp.get("neighbor_system")}" — cross-cabled port?')
         else:
             add(info, 'LLDP_MISSING',
                 'lldpd not running on server — install lldpd for full path validation')
diff --git a/tests/test_diagnose.py b/tests/test_diagnose.py
index e70425d..0b924f2 100644
--- a/tests/test_diagnose.py
+++ b/tests/test_diagnose.py
@@ -473,12 +473,27 @@ class TestAnalyze:
         assert 'LLDP_MISSING' in codes
 
     def test_lldp_mismatch_is_warning(self):
+        # The server's lldpd sees a different switch than the one this port belongs to.
         sections = self._sections(lldpctl={'available': True, 'neighbor_system': 'wrong-switch'})
-        switch_data = {'speed_mbps': 1000, 'lldp': {'system_name': 'core-sw-01'}}
+        switch_data = {'speed_mbps': 1000, 'switch_name': 'core-sw-01', 'lldp': {'system_name': 'server-a'}}
         result = DiagnosticsRunner.analyze(sections, switch_data)
         codes = [w['code'] for w in result['warnings']]
         assert 'LLDP_MISMATCH' in codes
 
+    def test_lldp_match_is_not_a_warning(self):
+        # Correct cabling: the switch sees the server, the server sees the switch.
+        sections = self._sections(lldpctl={'available': True, 'neighbor_system': 'core-sw-01'})
+        switch_data = {'speed_mbps': 1000, 'switch_name': 'core-sw-01', 'lldp': {'system_name': 'server-a'}}
+        result = DiagnosticsRunner.analyze(sections, switch_data)
+        codes = [w['code'] for w in result['warnings']]
+        assert 'LLDP_MISMATCH' not in codes
+
+    def test_lldp_without_switch_name_skips_check(self):
+        sections = self._sections(lldpctl={'available': True, 'neighbor_system': 'anything'})
+        result = DiagnosticsRunner.analyze(sections, {'speed_mbps': 1000, 'lldp': {'system_name': 'server-a'}})
+        codes = [w['code'] for w in result['warnings']]
+        assert 'LLDP_MISMATCH' not in codes
+
     def test_healthy_link_no_issues(self):
         result = DiagnosticsRunner.analyze(self._sections(), {})
         assert result['issues'] == []