diff --git a/src/seeder/dns.cpp b/src/seeder/dns.cpp
--- a/src/seeder/dns.cpp
+++ b/src/seeder/dns.cpp
@@ -78,6 +78,11 @@
         }
         // add dot in output
         if (!init) {
+            // The maximum size of a query name is 255. The buffer must have
+            // room for at least the '.' and a valid non-'.' character
+            if (bufused > 253) {
+                return -1;
+            }
             if (bufused == bufsize - 1) {
                 return -2;
             }
@@ -103,7 +108,7 @@
         }
         // copy label
         while (octet) {
-            if (*inpos == inend) {
+            if (*inpos == inend || bufused > 254) {
                 return -1;
             }
             if (bufused == bufsize - 1) {
diff --git a/src/seeder/test/seeder_tests.cpp b/src/seeder/test/seeder_tests.cpp
--- a/src/seeder/test/seeder_tests.cpp
+++ b/src/seeder/test/seeder_tests.cpp
@@ -112,7 +112,7 @@
     CheckParseName("my-domain.com");
 }
 
-BOOST_AUTO_TEST_CASE(parse_name_label_tests) {
+BOOST_AUTO_TEST_CASE(parse_name_label_and_name_length_tests) {
     // Check behavior for name with maximum length label
     std::string maxLengthLabel;
     for (size_t i = 0; i < MAX_LABEL_LENGTH; i++) {
@@ -123,6 +123,17 @@
 
     // Check that an oversized label causes an error
     CheckParseNameError("www." + maxLengthLabel + "a.com", -1);
+
+    // Check behavior for a name that is the maximum length
+    std::string maxLengthQName = maxLengthLabel + '.' + maxLengthLabel + '.' +
+                                 maxLengthLabel + '.' + maxLengthLabel;
+    BOOST_CHECK_EQUAL(maxLengthQName.size(), MAX_QUERY_NAME_LENGTH);
+    CheckParseName(maxLengthQName);
+
+    // Check that a query name that is too long causes an error
+    // Allocates an extra large buffer to guarantee an error is not caused by
+    // the buffer size
+    CheckParseNameError(maxLengthQName + "a", -1, 2 * maxLengthQName.size());
 }
 
 BOOST_AUTO_TEST_SUITE_END()