BIND uses the SOA minimum instead of the record's explicit TTL on the SOA
record on the slave server.  This will prevent (for example), an attempt to
delegate an IN-ADDR.ARPA. zone from APNIC, as the SOA records will not
match on master and slave.  Patch supplied by Mark Andrews of the ISC
(works against 8.2.2P3 and 8.2.2P5, pity about the line wrapping in the web
form):

diff -u -r8.98 db_load.c
--- src/bin/named/db_load.c     2000/02/21 21:27:41     8.98
+++ src/bin/named/db_load.c     2000/02/25 04:26:41
@@ -294,6 +294,7 @@
                default_warn = 1;
                clev = nlabels(in_origin);
                filenames = NULL;
+               zp->z_minimum = USE_MINIMUM;
        }
        ttl = default_ttl;

@@ -744,7 +746,7 @@
                                        zp->z_minimum = 0;
                                } else
                                        zp->z_minimum = n;
-                               if (default_ttl == USE_MINIMUM)
+                               if (ttl == USE_MINIMUM)
                                        ttl = n;
                                n = cp - (char *)data;
                                if (multiline) {
@@ -752,6 +754,7 @@
                                        buf[1] = '\0';
                                        if (buf[0] != ')')
                                                ERRTO("SOA \")\"");
+                                       multiline = 0;
                                        endline(fp);
                                }
                                 read_soa++;
@@ -973,7 +981,10 @@
                        case ns_t_cert:
                        case ns_t_sig: {
                                char *errmsg = NULL;
-                               int ret = parse_sec_rdata(buf, sizeof(buf),
0,
+                               int ret;
+                               if (ttl == USE_MINIMUM) /* no ttl set */
+                                       ttl = 0;
+                               ret = parse_sec_rdata(buf, sizeof(buf), 0,
                                                          data,
sizeof(data),
                                                          fp, zp, domain,
ttl,
                                                          type, domain_ctx,
@@ -1024,6 +1035,8 @@
                                        zp->z_origin);
                                continue;
                        }
+                       if (ttl == USE_MINIMUM) /* no ttl set */
+                               ttl = 0;
                        dp = savedata(class, type, (u_int32_t)ttl,
                                      (u_char *)data, (int)n);
                        dp->d_zone = zp - zones;