diff --git a/blockcheck2.d/standard/25-fake.sh b/blockcheck2.d/standard/25-fake.sh
index 8a744a8..aa7e52e 100644
--- a/blockcheck2.d/standard/25-fake.sh
+++ b/blockcheck2.d/standard/25-fake.sh
@@ -18,8 +18,8 @@ pktws_check_http()
 
 	need_fake=0
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	ok_any=0
 	ok=0
diff --git a/blockcheck2.d/standard/30-faked.sh b/blockcheck2.d/standard/30-faked.sh
index be24c48..54f4514 100644
--- a/blockcheck2.d/standard/30-faked.sh
+++ b/blockcheck2.d/standard/30-faked.sh
@@ -14,8 +14,8 @@ pktws_check_faked()
 	local PAYLOAD="--payload=$3"
 	local FAKED_PATTERN="$5"
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	# do not test fakedsplit if multisplit works
 	[ "$need_multisplit" = 0 -a "$SCANLEVEL" != force ] || splitfs=fakedsplit
diff --git a/blockcheck2.d/standard/35-hostfake.sh b/blockcheck2.d/standard/35-hostfake.sh
index 6d4c4e8..92ca0ed 100644
--- a/blockcheck2.d/standard/35-hostfake.sh
+++ b/blockcheck2.d/standard/35-hostfake.sh
@@ -37,8 +37,8 @@ pktws_check_hostfake()
 	local ok ttls attls f fooling
 	local PAYLOAD="--payload=$3"
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	need_hostfakesplit=0
 	ok=0
diff --git a/blockcheck2.d/standard/50-fake-multi.sh b/blockcheck2.d/standard/50-fake-multi.sh
index c650a35..f879321 100644
--- a/blockcheck2.d/standard/50-fake-multi.sh
+++ b/blockcheck2.d/standard/50-fake-multi.sh
@@ -16,8 +16,8 @@ pktws_check_http()
 		fake=fake_default_http
 	fi
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	# do not test fake + multisplit if multisplit works
 	[ "$need_multisplit" = 0 -a "$SCANLEVEL" != force ] || splitfs=multisplit
diff --git a/blockcheck2.d/standard/55-fake-faked.sh b/blockcheck2.d/standard/55-fake-faked.sh
index 281d8ce..8c903ff 100644
--- a/blockcheck2.d/standard/55-fake-faked.sh
+++ b/blockcheck2.d/standard/55-fake-faked.sh
@@ -16,8 +16,8 @@ pktws_check_http()
 		fake=fake_default_http
 	fi
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	# do not test fake + multisplit if multisplit works
 	[ "$need_fakedsplit" = 0 -a "$SCANLEVEL" != force ] || splitfs=fakedsplit
diff --git a/blockcheck2.d/standard/60-fake-hostfake.sh b/blockcheck2.d/standard/60-fake-hostfake.sh
index f9aa379..bddb863 100644
--- a/blockcheck2.d/standard/60-fake-hostfake.sh
+++ b/blockcheck2.d/standard/60-fake-hostfake.sh
@@ -33,8 +33,8 @@ pktws_check_hostfake()
 
 	[ "$need_hostfakesplit" = 0 ] && return 0
 
-	ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
-	attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
+	[ "$MAX_TTL" = 0 ] || ttls=$(seq -s ' ' $MIN_TTL $MAX_TTL)
+	[ "$MAX_AUTOTTL_DELTA" = 0 ] || attls=$(seq -s ' ' $MIN_AUTOTTL_DELTA $MAX_AUTOTTL_DELTA)
 
 	ok=0
 	for ttl in $ttls; do