diff --git a/src/config.cpp b/src/config.cpp
index cd7c77f..0fcc4bf 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -433,15 +433,25 @@ Config& Config::applyEnv()
     return *this;
 }
 
-Config Config::isolated()
+Config Config::isolated(int family)
 {
     Config ret;
 
     ret.udp_port = 0u;
     ret.tcp_port = 0u;
-    ret.interfaces.emplace_back("127.0.0.1");
     ret.auto_beacon = false;
-    ret.beaconDestinations.emplace_back("127.0.0.1");
+    switch(family) {
+    case AF_INET:
+        ret.interfaces.emplace_back("127.0.0.1");
+        ret.beaconDestinations.emplace_back("127.0.0.1");
+        break;
+    case AF_INET6:
+        ret.interfaces.emplace_back("::1");
+        ret.beaconDestinations.emplace_back("::1");
+        break;
+    default:
+        throw std::logic_error(SB()<<"Unsupported address family "<<family);
+    }
 
     return ret;
 }
diff --git a/src/pvxs/server.h b/src/pvxs/server.h
index ff826c7..948fe89 100644
--- a/src/pvxs/server.h
+++ b/src/pvxs/server.h
@@ -180,7 +180,8 @@ struct PVXS_API Config {
 
     //! Configuration limited to the local loopback interface on a randomly chosen port.
     //! Suitable for use in self-contained unit-tests.
-    static Config isolated();
+    //! @since UNRELEASED Address family argument added.
+    static Config isolated(int family=AF_INET);
 
     //! update using defined EPICS_PVA* environment variables
     Config& applyEnv();
diff --git a/src/udp_collector.cpp b/src/udp_collector.cpp
index 9205b86..c2b7540 100644
--- a/src/udp_collector.cpp
+++ b/src/udp_collector.cpp
@@ -315,7 +315,7 @@ void UDPCollector::process_one(const SockAddr &dest, const uint8_t *buf, size_t
         }
         server.setPort(port);
 
-        if(M.good() && origin==Loopback && (flags&pva_search_flags::Unicast) && dest.family()!=AF_UNSPEC) {
+        if(M.good() && origin==Loopback && (flags&pva_search_flags::Unicast) && dest.family()==AF_INET) {
             assert(buf==&this->buf[cmd_origin_tag_size]);
             // clear unicast flag in forwarded message
             *save_flags &= ~pva_search_flags::Unicast;
diff --git a/test/testget.cpp b/test/testget.cpp
index 2ee0e4d..8f43a8d 100644
--- a/test/testget.cpp
+++ b/test/testget.cpp
@@ -20,6 +20,7 @@
 #include <pvxs/sharedpv.h>
 #include <pvxs/source.h>
 #include <pvxs/nt.h>
+#include "evhelper.h"
 
 namespace {
 using namespace pvxs;
@@ -30,10 +31,10 @@ struct Tester {
     server::Server serv;
     client::Context cli;
 
-    Tester()
+    Tester(int family=AF_INET)
         :initial(nt::NTScalar{TypeCode::Int32}.create())
         ,mbox(server::SharedPV::buildReadonly())
-        ,serv(server::Config::isolated()
+        ,serv(server::Config::isolated(family)
               .build()
               .addPV("mailbox", mbox))
         ,cli(serv.clientConfig().build())
@@ -498,12 +499,18 @@ void testError(bool phase)
 
 MAIN(testget)
 {
-    testPlan(57);
+    testPlan(59);
     testSetup();
     logger_config_env();
+    bool canIPv6 = pvxs::impl::evsocket::canIPv6();
     Tester().testConnector();
     Tester().testWaiter();
-    Tester().loopback();
+    Tester(AF_INET).loopback();
+    if(canIPv6) {
+        Tester(AF_INET6).loopback();
+    } else {
+        testSkip(2, "No IPv6 Support");
+    }
     Tester().lazy();
     Tester().timeout();
     Tester().cancel();