diff --git a/basilisk/basilisk.c b/basilisk/basilisk.c
index e89be5c3c..cd3bfff76 100755
--- a/basilisk/basilisk.c
+++ b/basilisk/basilisk.c
@@ -252,16 +252,6 @@ int32_t basilisk_sendcmd(struct supernet_info *myinfo,char *destipaddr,char *typ
     return(n);
 }
 
-int32_t basilisk_blocksubmit(struct supernet_info *myinfo,struct iguana_info *virt,char *blockstr,bits256 hash2)
-{
-    int32_t recvlen; uint8_t *data,space[16384],*allocptr;
-    if ( (data= get_dataptr(BASILISK_HDROFFSET,&allocptr,&recvlen,space,sizeof(space),blockstr)) != 0 )
-        gecko_blockarrived(myinfo,virt,"127.0.0.1",data,recvlen,hash2);
-    if ( allocptr != 0 )
-        free(allocptr);
-    return(recvlen);
-}
-
 void basilisk_p2p(void *_myinfo,void *_addr,char *senderip,uint8_t *data,int32_t datalen,char *type,int32_t encrypted)
 {
     uint32_t ipbits,basilisktag; int32_t msglen,len=0; void *ptr = 0; uint8_t space[8192]; bits256 senderpub; struct supernet_info *myinfo = _myinfo;
@@ -359,7 +349,7 @@ struct basilisk_item *basilisk_issueremote(struct supernet_info *myinfo,int32_t
 
 struct basilisk_item *basilisk_requestservice(struct supernet_info *myinfo,char *CMD,int32_t blockflag,cJSON *valsobj,bits256 hash,uint8_t *data,int32_t datalen,uint32_t nBits)
 {
-    int32_t minresults,timeoutmillis,numsent,delaymillis,encryptflag; struct basilisk_item *ptr; char buf[4096],*symbol,*str = 0; struct iguana_info *virt,*btcd;
+    int32_t minresults,timeoutmillis,numsent,delaymillis,encryptflag,fanout; struct basilisk_item *ptr; char buf[4096],*symbol,*str = 0; struct iguana_info *virt,*btcd;
     if ( (btcd= iguana_coinfind("BTCD")) != 0 && btcd->RELAYNODE != 0 )
         jaddnum(valsobj,"iamrelay",1);
     basilisk_addhexstr(&str,valsobj,buf,sizeof(buf),data,datalen);
@@ -373,6 +363,9 @@ struct basilisk_item *basilisk_requestservice(struct supernet_info *myinfo,char
         minresults = 1;
     if ( (timeoutmillis= jint(valsobj,"timeout")) == 0 )
         timeoutmillis = BASILISK_TIMEOUT;
+    if ( jobj(valsobj,"fanout") == 0 )
+        fanout = 1;
+    else fanout = jint(valsobj,"fanout");
     if ( (symbol= jstr(valsobj,"coin")) != 0 || (symbol= jstr(valsobj,"symbol")) != 0 )
     {
         if ( (virt= iguana_coinfind(symbol)) != 0 )
@@ -384,7 +377,7 @@ struct basilisk_item *basilisk_requestservice(struct supernet_info *myinfo,char
     }
     encryptflag = jint(valsobj,"encrypt");
     delaymillis = jint(valsobj,"delay");
-    ptr = basilisk_issueremote(myinfo,&numsent,CMD,"BTCD",blockflag,valsobj,1,minresults,0,timeoutmillis,0,0,encryptflag,delaymillis,nBits);
+    ptr = basilisk_issueremote(myinfo,&numsent,CMD,"BTCD",blockflag,valsobj,fanout,minresults,0,timeoutmillis,0,0,encryptflag,delaymillis,nBits);
     return(ptr);
 }
 
@@ -416,6 +409,24 @@ char *basilisk_standardservice(char *CMD,struct supernet_info *myinfo,bits256 ha
     return(jprint(retjson,1));
 }
 
+int32_t basilisk_blocksubmit(struct supernet_info *myinfo,struct iguana_info *btcd,struct iguana_info *virt,char *blockstr,bits256 hash2)
+{
+    int32_t datalen; uint8_t *data,space[16384],*allocptr; cJSON *valsobj; char *str;
+    if ( (data= get_dataptr(sizeof(struct iguana_msghdr) + BASILISK_HDROFFSET,&allocptr,&datalen,space,sizeof(space),blockstr)) != 0 )
+    {
+        gecko_blockarrived(myinfo,virt,"127.0.0.1",data,datalen,hash2);
+        valsobj = cJSON_CreateObject();
+        jaddnum(valsobj,"fanout",-1);
+        jaddstr(valsobj,"symbol",virt->symbol);
+        if ( (str= basilisk_standardservice("BLK",myinfo,hash2,valsobj,blockstr,0)) != 0 )
+            free(str);
+        free_json(valsobj);
+    }
+    if ( allocptr != 0 )
+        free(allocptr);
+    return(0);
+}
+
 #include "basilisk_bitcoin.c"
 #include "basilisk_nxt.c"
 #include "basilisk_ether.c"
@@ -1021,7 +1032,7 @@ void basilisk_msgprocess(struct supernet_info *myinfo,void *_addr,uint32_t sende
     symbol = "BTCD";
     if ( (valsobj= cJSON_Parse((char *)data)) != 0 )
     {
-        //printf("MSGVALS.(%s)\n",(char *)data);
+        printf("MSGVALS.(%s)\n",(char *)data);
         if ( jobj(valsobj,"coin") != 0 )
             coin = iguana_coinfind(jstr(valsobj,"coin"));
         else if ( jobj(valsobj,"symbol") != 0 )
@@ -1071,7 +1082,7 @@ void basilisk_msgprocess(struct supernet_info *myinfo,void *_addr,uint32_t sende
         CMD[i] = toupper((int32_t)CMD[i]);
         cmd[i] = tolower((int32_t)CMD[i]);
     }
-    //printf("MSGPROCESS.(%s) tag.%d\n",(char *)data,basilisktag);
+    printf("MSGPROCESS.(%s) tag.%d\n",(char *)data,basilisktag);
     myinfo->basilisk_busy = 1;
     if ( valsobj != 0 )
     {
diff --git a/gecko/gecko_blocks.c b/gecko/gecko_blocks.c
index 64b498b70..c3218d141 100755
--- a/gecko/gecko_blocks.c
+++ b/gecko/gecko_blocks.c
@@ -151,7 +151,7 @@ int32_t gecko_hwmset(struct iguana_info *virt,struct iguana_txblock *txdata,stru
 
 char *gecko_blockarrived(struct supernet_info *myinfo,struct iguana_info *virt,char *remoteaddr,uint8_t *data,int32_t datalen,bits256 hash2)
 {
-    struct iguana_txblock txdata; int32_t valid,adjacent,n,i,j,len = -1; struct iguana_block *block,*prev;
+    struct iguana_txblock txdata; int32_t height,valid,adjacent,gap,n,i,j,len = -1; struct iguana_block *block,*prev; struct iguana_txid tx; char str[65]; bits256 txid; struct iguana_msgtx *txs;
     memset(&txdata,0,sizeof(txdata));
     iguana_memreset(&virt->TXMEM);
     if ( (n= iguana_gentxarray(virt,&virt->TXMEM,&txdata,&len,data,datalen)) == datalen )
@@ -161,6 +161,16 @@ char *gecko_blockarrived(struct supernet_info *myinfo,struct iguana_info *virt,c
             printf("gecko_blockarrived: mismatched hash2\n");
             return(clonestr("{\"error\":\"gecko block hash2 mismatch\"}"));
         }
+        txs = virt->TXMEM.ptr;
+        for (i=0; i<txdata.zblock.RO.txn_count; i++)
+        {
+            txid = txs[i].txid;
+            if ( iguana_txidfind(virt,&height,&tx,txid,virt->bundlescount-1) != 0 && height >= 0 )
+            {
+                printf("gecko_blockarrived: duplicate.[%d] txid.%s\n",i,bits256_str(str,txid));
+                return(clonestr("{\"error\":\"gecko block duplicate txid\"}"));
+            }
+        }
         txdata.zblock.RO.allocsize = iguana_ROallocsize(virt);
         if ( iguana_blockvalidate(virt,&valid,(struct iguana_block *)&txdata.zblock,1) < 0 )
         {
@@ -182,21 +192,44 @@ char *gecko_blockarrived(struct supernet_info *myinfo,struct iguana_info *virt,c
             if ( i == 0 )
                 adjacent = prev->height;
             //printf("i.%d prevht.%d adjacent.%d hwm.%d\n",i,prev->height,adjacent,virt->blocks.hwmchain.height);
-            if ( prev->height >= 0 )
+            if ( prev->height >= 0 && prev->mainchain != 0 )
             {
-                txdata.zblock.height = block->height = adjacent + 1;
-                if ( block->height > virt->blocks.hwmchain.height ) // longest chain wins
+                if ( (adjacent + 1) > virt->blocks.hwmchain.height ) // longest chain wins
                 {
                     //printf("new HWM %d adjacent.%d prev.%d i.%d\n",block->height,adjacent,prev->height,i);
-                    txdata.zblock.mainchain = block->mainchain = 1;
+                    if ( (gap= (block->height - virt->blocks.hwmchain.height)) > 1 )
+                    {
+                        prev = iguana_blockfind("geckoclear",virt,virt->blocks.hwmchain.RO.prev_block);
+                        for (j=0; j<gap && prev!=0; j++)
+                        {
+                            printf("%d of %d: protected.%d unlink %s ht.%d from mainchain, newhwm ht.%d\n",j,gap,prev->protected,bits256_str(str,prev->RO.hash2),prev->height,block->height);
+                            if ( prev->protected != 0 )
+                            {
+                                printf("REJECT block: cant overwrite protected block\n");
+                                return(clonestr("{\"error\":\"gecko block cant override protected block\"}"));
+                            }
+                            prev->mainchain = 0;
+                            prev = iguana_blockfind("geckoclrprev",virt,prev->RO.prev_block);
+                        }
+                    }
                     prev = block;
-                    // probably should clear mainchain bits in old path
                     for (j=0; j<=i; j++)
                     {
                         if ( (prev= iguana_blockfind("geckoprev",virt,prev->RO.prev_block)) == 0 )
                             return(clonestr("{\"error\":\"gecko block mainchain link error\"}"));
-                        prev->mainchain = 1;
+                        if ( prev->protected == 0 || prev->height == (adjacent + 1 - j) )
+                        {
+                            prev->mainchain = 1;
+                            prev->height = (adjacent + 1 - j);
+                        }
+                        else
+                        {
+                            printf("REJECT block: cant change height of protected block: ht.%d vs %d\n",adjacent + 1 - j, prev->height);
+                            return(clonestr("{\"error\":\"gecko block cant override protected block's height\"}"));
+                        }
                     }
+                    txdata.zblock.height = block->height;
+                    txdata.zblock.mainchain = block->mainchain = 1;
                     if ( gecko_hwmset(virt,&txdata,virt->TXMEM.ptr,data,datalen,i+1) >= 0 )
                         return(clonestr("{\"result\":\"gecko block created\"}"));
                     else return(clonestr("{\"error\":\"gecko error creating hwmblock\"}"));
@@ -214,6 +247,12 @@ char *basilisk_respond_geckoblock(struct supernet_info *myinfo,char *CMD,void *a
     printf("got geckoblock len.%d from (%s) %s\n",datalen,remoteaddr!=0?remoteaddr:"",jprint(valsobj,0));
     if ( (symbol= jstr(valsobj,"coin")) != 0 && (virt= iguana_coinfind(symbol)) != 0 )
     {
+        if ( iguana_blockfind("geckoblock",virt,hash2) != 0 )
+        {
+            char str[65];
+            printf("REJECT: duplicate block %s\n",bits256_str(str,hash2));
+            return(clonestr("{\"error\":\"duplicate block rejected\"}"));
+        }
         hdrsize = (virt->chain->zcash != 0) ? sizeof(struct iguana_msgblockhdr_zcash) : sizeof(struct iguana_msgblockhdr);
         nBits = gecko_nBits(virt,&prevtimestamp,(struct iguana_block *)&virt->blocks.hwmchain,GECKO_DIFFITERS);
         if ( gecko_blocknonce_verify(virt,data,hdrsize,nBits,virt->blocks.hwmchain.RO.timestamp,prevtimestamp) == 0 )
@@ -229,7 +268,8 @@ char *basilisk_respond_geckoblock(struct supernet_info *myinfo,char *CMD,void *a
 
 int32_t basilisk_respond_geckogetblock(struct supernet_info *myinfo,struct iguana_info *virt,uint8_t *serialized,int32_t maxsize,cJSON *valsobj,bits256 hash2)
 {
-    int32_t datalen = 0;
+    int32_t datalen = 0; char str[65];
+    printf("GOT request for block.(%s)\n",bits256_str(str,hash2));
     // find block and set serialized
     return(datalen);
 }
diff --git a/gecko/gecko_miner.c b/gecko/gecko_miner.c
index 53730b4eb..1609ab47e 100755
--- a/gecko/gecko_miner.c
+++ b/gecko/gecko_miner.c
@@ -296,12 +296,12 @@ cJSON *gecko_paymentsobj(struct supernet_info *myinfo,cJSON *txjson,cJSON *valso
     return(txjson);
 }
 
-void gecko_blocksubmit(struct supernet_info *myinfo,struct iguana_info *virt,char *blockstr,bits256 hash2)
+void gecko_blocksubmit(struct supernet_info *myinfo,struct iguana_info *btcd,struct iguana_info *virt,char *blockstr,bits256 hash2)
 {
     uint8_t *data,space[16384],*allocptr=0; int32_t i,len,numranked=0; struct iguana_peers *peers; struct iguana_peer *addr;
     if ( (peers= virt->peers) == 0 || (numranked= peers->numranked) == 0 )
-        basilisk_blocksubmit(myinfo,virt,blockstr,hash2);
-    else
+        basilisk_blocksubmit(myinfo,btcd,virt,blockstr,hash2);
+    else // physical node for geckochain
     {
         if ( (data= get_dataptr(sizeof(struct iguana_msghdr),&allocptr,&len,space,sizeof(space),blockstr)) != 0 )
         {
@@ -335,7 +335,7 @@ void gecko_miner(struct supernet_info *myinfo,struct iguana_info *btcd,struct ig
         if ( (blockstr= gecko_createblock(myinfo,virt->chain->estblocktime,prevtimestamp,btcd,virt->chain->isPoS,(void *)&newblock,virt->symbol,txptrs,txn_count,maxmillis,minerpubkey33,reward)) != 0 )
         {
             char str[65]; printf("%s.%x %s %u %d %.8f %d\n",virt->symbol,newblock.RO.bits,bits256_str(str,newblock.RO.hash2),newblock.RO.timestamp,newblock.height,dstr(reward),newblock.RO.txn_count);
-            gecko_blocksubmit(myinfo,virt,blockstr,newblock.RO.hash2);
+            gecko_blocksubmit(myinfo,btcd,virt,blockstr,newblock.RO.hash2);
             free(blockstr);
         }
         if ( txptrs != (void *)space )
diff --git a/includes/iguana_funcs.h b/includes/iguana_funcs.h
index 32b376b46..4c8d4b56e 100755
--- a/includes/iguana_funcs.h
+++ b/includes/iguana_funcs.h
@@ -487,7 +487,7 @@ void iguana_blockzcopy(uint8_t zcash,struct iguana_block *dest,struct iguana_blo
 int32_t iguana_blocksizecheck(char *debugstr,uint8_t zcash,struct iguana_block *block);
 void basilisk_miner(struct supernet_info *myinfo,struct iguana_info *btcd,struct iguana_info *virt,int32_t maxmillis,char *mineraddr);
 int32_t bitcoin_pubkeyspend(uint8_t *script,int32_t n,uint8_t pubkey[66]);
-int32_t basilisk_blocksubmit(struct supernet_info *myinfo,struct iguana_info *virt,char *blockstr,bits256 hash2);
+int32_t basilisk_blocksubmit(struct supernet_info *myinfo,struct iguana_info *btcd,struct iguana_info *virt,char *blockstr,bits256 hash2);
 struct supernet_info *SuperNET_MYINFO(char *passphrase);
 bits256 calc_categoryhashes(bits256 *subhashp,char *category,char *subcategory);
 struct gecko_chain *category_find(bits256 categoryhash,bits256 subhash);
diff --git a/includes/iguana_structs.h b/includes/iguana_structs.h
index 1cd38fc28..2217b9cb6 100755
--- a/includes/iguana_structs.h
+++ b/includes/iguana_structs.h
@@ -185,7 +185,7 @@ struct iguana_zblockRO
 } __attribute__((packed));
 
 #define iguana_blockfields      double PoW; \
-int32_t height,fpos; uint32_t fpipbits,issued,lag:20,peerid:12; \
+int32_t height,fpos; uint32_t fpipbits,issued,lag:19,protected:1,peerid:12; \
 uint16_t hdrsi:15,mainchain:1,bundlei:11,valid:1,queued:1,txvalid:1,newtx:1,processed:1; \
 UT_hash_handle hh; struct iguana_bundlereq *req; \
 struct iguana_blockRO RO
@@ -375,7 +375,6 @@ struct hhbits256 { UT_hash_handle hh; bits256 txid; int32_t height; uint16_t fir
 
 struct iguana_monitorinfo { bits256 txid; int32_t numreported; uint8_t peerbits[IGUANA_MAXPEERS >> 3]; };
 
-
 struct iguana_info
 {
     UT_hash_handle hh;