diff --git a/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor b/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor
index 30ece7b..511c24c 100644
--- a/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor
+++ b/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor
@@ -58,6 +58,17 @@
                         }
                     </select>
                 </div>
+                @* Task 17: free-text Node filter — exact match against the
+                   SiteCall.SourceNode column. The Source site dropdown narrows
+                   to a site; Node narrows further within that site (or across
+                   sites if Source site is "Any"). *@
+                <div class="col-auto">
+                    <label class="form-label small mb-1" for="sc-node">Node</label>
+                    <input id="sc-node" type="text" class="form-control form-control-sm"
+                           style="min-width: 150px;" placeholder="Any"
+                           data-test="site-calls-filter-node"
+                           @bind="_nodeFilter" />
+                </div>
                 <div class="col-auto">
                     <label class="form-label small mb-1" for="sc-from">From</label>
                     <input id="sc-from" type="datetime-local" class="form-control form-control-sm"
@@ -125,6 +136,7 @@
                     <tr>
                         <th>Tracked operation</th>
                         <th>Source site</th>
+                        <th>Node</th>
                         <th>Channel</th>
                         <th>Target</th>
                         <th>Status</th>
@@ -143,6 +155,7 @@
                             title="Double-click for full detail">
                             <td><code class="small" title="@c.TrackedOperationId">@ShortId(c.TrackedOperationId)</code></td>
                             <td><span class="small">@SiteName(c.SourceSite)</span></td>
+                            <td><span class="small">@(c.SourceNode ?? "—")</span></td>
                             <td>@c.Channel</td>
                             <td>@c.Target</td>
                             <td>
@@ -253,6 +266,9 @@
                             <dt class="col-sm-3">Source site</dt>
                             <dd class="col-sm-9">@SiteName(det.SourceSite)</dd>
 
+                            <dt class="col-sm-3">Source node</dt>
+                            <dd class="col-sm-9">@(string.IsNullOrEmpty(d.SourceNode) ? "—" : d.SourceNode)</dd>
+
                             <dt class="col-sm-3">Channel</dt>
                             <dd class="col-sm-9">@det.Channel</dd>
 
diff --git a/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor.cs b/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor.cs
index c8f0a21..726a025 100644
--- a/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor.cs
+++ b/src/ScadaLink.CentralUI/Components/Pages/SiteCalls/SiteCallsReport.razor.cs
@@ -82,6 +82,7 @@ public partial class SiteCallsReport
     private string _channelFilter = string.Empty;
     private string _siteFilter = string.Empty;
     private string _targetFilter = string.Empty;
+    private string _nodeFilter = string.Empty;
     private bool _stuckOnly;
     private DateTime? _fromFilter;
     private DateTime? _toFilter;
@@ -204,7 +205,8 @@ public partial class SiteCallsReport
                 ToUtc: ToUtc(_toFilter),
                 AfterCreatedAtUtc: cursor.AfterCreatedAtUtc,
                 AfterId: cursor.AfterId,
-                PageSize: PageSize);
+                PageSize: PageSize,
+                SourceNodeFilter: NullIfEmpty(_nodeFilter));
 
             var response = await CommunicationService.QuerySiteCallsAsync(request);
             if (response.Success)
@@ -393,6 +395,7 @@ public partial class SiteCallsReport
         _channelFilter = string.Empty;
         _siteFilter = string.Empty;
         _targetFilter = string.Empty;
+        _nodeFilter = string.Empty;
         _stuckOnly = false;
         _fromFilter = null;
         _toFilter = null;
@@ -403,6 +406,7 @@ public partial class SiteCallsReport
         !string.IsNullOrEmpty(_channelFilter) ||
         !string.IsNullOrEmpty(_siteFilter) ||
         !string.IsNullOrEmpty(_targetFilter) ||
+        !string.IsNullOrEmpty(_nodeFilter) ||
         _stuckOnly ||
         _fromFilter != null ||
         _toFilter != null;
diff --git a/src/ScadaLink.Commons/Messages/Audit/SiteCallQueries.cs b/src/ScadaLink.Commons/Messages/Audit/SiteCallQueries.cs
index d5c98a4..93658c5 100644
--- a/src/ScadaLink.Commons/Messages/Audit/SiteCallQueries.cs
+++ b/src/ScadaLink.Commons/Messages/Audit/SiteCallQueries.cs
@@ -33,7 +33,8 @@ public sealed record SiteCallQueryRequest(
     DateTime? ToUtc,
     DateTime? AfterCreatedAtUtc,
     Guid? AfterId,
-    int PageSize);
+    int PageSize,
+    string? SourceNodeFilter = null);
 
 /// <summary>
 /// A single <c>SiteCalls</c> row summarised for the Site Calls UI grid. Carries
@@ -61,7 +62,8 @@ public sealed record SiteCallSummary(
     DateTime CreatedAtUtc,
     DateTime UpdatedAtUtc,
     DateTime? TerminalAtUtc,
-    bool IsStuck);
+    bool IsStuck,
+    string? SourceNode = null);
 
 /// <summary>
 /// Central -> Site Calls UI: paginated response for a <see cref="SiteCallQueryRequest"/>.
diff --git a/src/ScadaLink.Commons/Types/Audit/SiteCallQueryFilter.cs b/src/ScadaLink.Commons/Types/Audit/SiteCallQueryFilter.cs
index 63f0c58..3624191 100644
--- a/src/ScadaLink.Commons/Types/Audit/SiteCallQueryFilter.cs
+++ b/src/ScadaLink.Commons/Types/Audit/SiteCallQueryFilter.cs
@@ -26,6 +26,11 @@ namespace ScadaLink.Commons.Types.Audit;
 /// keeps the "StuckOnly" filter honest so paging never returns under-filled
 /// pages with a non-null next cursor.
 /// </param>
+/// <param name="SourceNode">
+/// Restrict to cached calls originating at a specific cluster node (e.g.
+/// <c>"site-plant-a-node-a"</c>). Exact match; <c>null</c> means "do not
+/// constrain". Rows with NULL <c>SourceNode</c> are excluded when set.
+/// </param>
 public sealed record SiteCallQueryFilter(
     string? Channel = null,
     string? SourceSite = null,
@@ -33,4 +38,5 @@ public sealed record SiteCallQueryFilter(
     string? Target = null,
     DateTime? FromUtc = null,
     DateTime? ToUtc = null,
-    DateTime? StuckCutoffUtc = null);
+    DateTime? StuckCutoffUtc = null,
+    string? SourceNode = null);
diff --git a/src/ScadaLink.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs b/src/ScadaLink.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
index a06282f..ca3c226 100644
--- a/src/ScadaLink.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
+++ b/src/ScadaLink.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
@@ -204,6 +204,7 @@ SELECT TOP ({paging.PageSize})
 FROM dbo.SiteCalls
 WHERE ({filter.Channel} IS NULL OR Channel = {filter.Channel})
   AND ({filter.SourceSite} IS NULL OR SourceSite = {filter.SourceSite})
+  AND ({filter.SourceNode} IS NULL OR SourceNode = {filter.SourceNode})
   AND ({filter.Status} IS NULL OR Status = {filter.Status})
   AND ({filter.Target} IS NULL OR Target = {filter.Target})
   AND ({fromUtc} IS NULL OR CreatedAtUtc >= {fromUtc})
diff --git a/src/ScadaLink.SiteCallAudit/SiteCallAuditActor.cs b/src/ScadaLink.SiteCallAudit/SiteCallAuditActor.cs
index 8078060..7539f3a 100644
--- a/src/ScadaLink.SiteCallAudit/SiteCallAuditActor.cs
+++ b/src/ScadaLink.SiteCallAudit/SiteCallAuditActor.cs
@@ -232,7 +232,8 @@ public class SiteCallAuditActor : ReceiveActor
             // TerminalAtUtc IS NULL AND CreatedAtUtc < cutoff composes with the
             // keyset cursor, so the page is always honest (full pages, no empty
             // pages with a non-null next cursor).
-            StuckCutoffUtc: request.StuckOnly ? stuckCutoff : null);
+            StuckCutoffUtc: request.StuckOnly ? stuckCutoff : null,
+            SourceNode: NullIfBlank(request.SourceNodeFilter));
 
         var pageSize = Math.Clamp(request.PageSize, 1, MaxPageSize);
         var paging = new SiteCallPaging(
@@ -633,7 +634,8 @@ public class SiteCallAuditActor : ReceiveActor
             CreatedAtUtc: row.CreatedAtUtc,
             UpdatedAtUtc: row.UpdatedAtUtc,
             TerminalAtUtc: row.TerminalAtUtc,
-            IsStuck: IsStuck(row, stuckCutoff));
+            IsStuck: IsStuck(row, stuckCutoff),
+            SourceNode: row.SourceNode);
     }
 
     private static SiteCallDetail ToDetail(SiteCall row)
diff --git a/tests/ScadaLink.SiteCallAudit.Tests/SiteCallAuditActorTests.cs b/tests/ScadaLink.SiteCallAudit.Tests/SiteCallAuditActorTests.cs
index 42093c5..0d6fd26 100644
--- a/tests/ScadaLink.SiteCallAudit.Tests/SiteCallAuditActorTests.cs
+++ b/tests/ScadaLink.SiteCallAudit.Tests/SiteCallAuditActorTests.cs
@@ -223,6 +223,43 @@ public class SiteCallAuditActorTests : TestKit, IClassFixture<MsSqlMigrationFixt
         Assert.Equal(response.SiteCalls[^1].TrackedOperationId, response.NextAfterId);
     }
 
+    [SkippableFact]
+    public async Task SiteCallQueryRequest_FilterBySourceNode_ReturnsMatchingSummaries()
+    {
+        // Task 17: the new Node filter input pushes a string into
+        // SiteCallQueryRequest.SourceNodeFilter — the actor must thread it
+        // onto SiteCallQueryFilter.SourceNode and the response summaries must
+        // mirror the row's SourceNode column.
+        Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+
+        var siteId = NewSiteId();
+        await using var context = CreateContext();
+        var repo = new SiteCallAuditRepository(context);
+        var actor = CreateActor(repo);
+
+        var t0 = new DateTime(2026, 5, 20, 14, 0, 0, DateTimeKind.Utc);
+        await repo.UpsertAsync(NewRow(
+            TrackedOperationId.New(), siteId, status: "Attempted",
+            createdAtUtc: t0, sourceNode: "site-plant-a-node-a"));
+        await repo.UpsertAsync(NewRow(
+            TrackedOperationId.New(), siteId, status: "Delivered",
+            createdAtUtc: t0.AddMinutes(1), terminal: true, sourceNode: "site-plant-a-node-b"));
+
+        actor.Tell(
+            new SiteCallQueryRequest(
+                "corr-node", StatusFilter: null, SourceSiteFilter: siteId, ChannelFilter: null,
+                TargetKeyword: null, StuckOnly: false, FromUtc: null, ToUtc: null,
+                AfterCreatedAtUtc: null, AfterId: null, PageSize: 50,
+                SourceNodeFilter: "site-plant-a-node-a"),
+            TestActor);
+
+        var response = ExpectMsg<SiteCallQueryResponse>(TimeSpan.FromSeconds(10));
+        Assert.True(response.Success);
+        Assert.Single(response.SiteCalls);
+        Assert.Equal("site-plant-a-node-a", response.SiteCalls[0].SourceNode);
+        Assert.Equal("Attempted", response.SiteCalls[0].Status);
+    }
+
     [SkippableFact]
     public async Task SiteCallQueryRequest_KeysetPaging_AdvancesViaCursor()
     {