diff --git a/sys/src/9/ip/icmp.c b/sys/src/9/ip/icmp.c
index 9dd5c9414..3f5a80e21 100644
--- a/sys/src/9/ip/icmp.c
+++ b/sys/src/9/ip/icmp.c
@@ -366,7 +366,7 @@ icmpiput(Proto *icmp, Ipifc*, Block *bp)
 	case EchoRequest:
 		if (iplen < n)
 			bp = trimblock(bp, 0, iplen);
-		r = mkechoreply(bp);
+		r = mkechoreply(concatblock(bp));
 		ipriv->out[EchoReply]++;
 		ipoput4(icmp->f, r, 0, MAXTTL, DFLTTOS, nil);
 		break;
diff --git a/sys/src/9/ip/icmp6.c b/sys/src/9/ip/icmp6.c
index 458280b27..7335a3c5e 100644
--- a/sys/src/9/ip/icmp6.c
+++ b/sys/src/9/ip/icmp6.c
@@ -734,7 +734,7 @@ icmpiput6(Proto *icmp, Ipifc *ipifc, Block *bp)
 
 	switch(p->type) {
 	case EchoRequestV6:
-		r = mkechoreply6(bp, ipifc);
+		r = mkechoreply6(concatblock(bp), ipifc);
 		if(r == nil)
 			goto raise;
 		ipriv->out[EchoReply]++;
diff --git a/sys/src/9/ip/ip.c b/sys/src/9/ip/ip.c
index 19aef70a4..40fc9380e 100644
--- a/sys/src/9/ip/ip.c
+++ b/sys/src/9/ip/ip.c
@@ -208,7 +208,6 @@ ipoput4(Fs *f, Block *bp, int gating, int ttl, int tos, Conv *c)
 		eh->cksum[0] = 0;
 		eh->cksum[1] = 0;
 		hnputs(eh->cksum, ipcsum(&eh->vihl));
-		assert(bp->next == nil);
 		ifc->m->bwrite(ifc, bp, V4, gate);
 		runlock(ifc);
 		poperror();