diff --git a/src/seeder/dns.h b/src/seeder/dns.h
--- a/src/seeder/dns.h
+++ b/src/seeder/dns.h
@@ -8,6 +8,13 @@
 #include <cstddef>
 #include <cstdint>
 
+const static uint8_t DNS_NO_ERROR = 0;
+const static uint8_t DNS_FORMAT_ERROR = 1;
+const static uint8_t DNS_SERVER_FAILURE = 2;
+const static uint8_t DNS_NAME_ERROR = 3;
+const static uint8_t DNS_NOT_IMPLEMENTED = 4;
+const static uint8_t DNS_REFUSED = 5;
+
 struct addr_t {
     int v;
     union {
diff --git a/src/seeder/dns.cpp b/src/seeder/dns.cpp
--- a/src/seeder/dns.cpp
+++ b/src/seeder/dns.cpp
@@ -349,7 +349,7 @@
 
 static ssize_t dnshandle(dns_opt_t *opt, const uint8_t *inbuf, size_t insize,
                          uint8_t *outbuf) {
-    int error = 0;
+    int error = DNS_NO_ERROR;
     if (insize < 12) {
         // DNS header
         return -1;
@@ -371,14 +371,14 @@
     // check qr
     if (inbuf[2] & 128) {
         /* fprintf(stdout, "Got response?\n"); */
-        error = 1;
+        error = DNS_FORMAT_ERROR;
         goto error;
     }
 
     // check opcode
     if (((inbuf[2] & 120) >> 3) != 0) {
         /* fprintf(stdout, "Opcode nonzero?\n"); */
-        error = 4;
+        error = DNS_NOT_IMPLEMENTED;
         goto error;
     }
 
@@ -390,13 +390,13 @@
     nquestion = (inbuf[4] << 8) + inbuf[5];
     if (nquestion == 0) {
         /* fprintf(stdout, "No questions?\n"); */
-        error = 0;
+        error = DNS_NO_ERROR;
         goto error;
     }
 
     if (nquestion > 1) {
         /* fprintf(stdout, "Multiple questions %i?\n", nquestion); */
-        error = 4;
+        error = DNS_NOT_IMPLEMENTED;
         goto error;
     }
 
@@ -407,12 +407,12 @@
         int offset = inpos - inbuf;
         int ret = parse_name(&inpos, inend, inbuf, name, 256);
         if (ret == -1) {
-            error = 1;
+            error = DNS_FORMAT_ERROR;
             goto error;
         }
 
         if (ret == -2) {
-            error = 5;
+            error = DNS_REFUSED;
             goto error;
         }
 
@@ -420,12 +420,12 @@
         if (strcasecmp(name, opt->host) &&
             (namel < hostl + 2 || name[namel - hostl - 1] != '.' ||
              strcasecmp(name + namel - hostl, opt->host))) {
-            error = 5;
+            error = DNS_REFUSED;
             goto error;
         }
 
         if (inend - inpos < 4) {
-            error = 1;
+            error = DNS_FORMAT_ERROR;
             goto error;
         }