diff --git a/tests/common/config.py b/tests/common/config.py
index 2735627..3a3717c 100644
--- a/tests/common/config.py
+++ b/tests/common/config.py
@@ -490,6 +490,13 @@ def setup_tunnel_routes(r1con, r2con, tun_ipv6, network3):
     return r1ipnh, r1ip6nh, r2ipnh, r2ip6nh
 
 
+def esp_args_filter_dir(direction, esp_args):
+    """Filter out esp args inappropriate for the direction."""
+    if direction != "in":
+        esp_args = re.sub(r"replay-window \d+", "", esp_args)
+    return esp_args
+
+
 def esp_flags_filter_dir(direction, esp_flags):
     """Filter out esp flags inappropriate for the direction."""
     if direction == "in":
@@ -523,6 +530,7 @@ async def setup_policy_tun(
     trex=False,
     r1only=False,
     ipsec_intf="eth2",
+    esp_args="",
     esp_flags="",
     iptfs_opts="",
     ipv4=True,
@@ -594,12 +602,12 @@ async def setup_policy_tun(
         #
         direction = "out" if r == r1 else "in"
         eflags = esp_flags_filter_dir(direction, esp_flags)
-        esp_args = "replay-window 128" if direction == "in" else ""
+        eargs = esp_args_filter_dir(direction, esp_args)
         repl.cmd_raises(
             (
                 f"ip xfrm state add src {r1ip} dst {r2ip} proto esp "
                 f"spi {spi_1to2} mode {mode} {sa_auth} {sa_enc} "
-                f"{esp_args} {eflags} reqid {reqid_1to2} dir {direction} "
+                f"{eargs} {eflags} reqid {reqid_1to2} dir {direction} "
                 # f"reqid {reqid_1to2} "
             )
             + iptfs_opts_filter_dir(direction, iptfs_opts)
@@ -607,12 +615,12 @@ async def setup_policy_tun(
 
         direction = "in" if r == r1 else "out"
         eflags = esp_flags_filter_dir(direction, esp_flags)
-        esp_args = "replay-window 128" if direction == "in" else ""
+        eargs = esp_args_filter_dir(direction, esp_args)
         repl.cmd_raises(
             (
                 f"ip xfrm state add src {r2ip} dst {r1ip} proto esp "
                 f"spi {spi_2to1} mode {mode} {sa_auth} {sa_enc} "
-                f"{esp_args} {eflags} reqid {reqid_2to1} dir {direction} "
+                f"{eargs} {eflags} reqid {reqid_2to1} dir {direction} "
                 # f"reqid {reqid_2to1} "
             )
             + iptfs_opts_filter_dir(direction, iptfs_opts)
@@ -757,6 +765,7 @@ async def setup_routed_tun(
     r1only=False,
     ipsec_intf="eth2",
     iptfs_opts="",
+    esp_args="",
     esp_flags="",
     ipv4=True,
     ipv6=False,
@@ -835,23 +844,23 @@ async def setup_routed_tun(
 
         direction = "out" if r == r1 else "in"
         eflags = esp_flags_filter_dir(direction, esp_flags)
-        esp_args = "replay-window 128" if direction == "in" else ""
+        eargs = esp_args_filter_dir(direction, esp_args)
         repl.cmd_raises(
             (
                 f"ip xfrm state add src {r1ip} dst {r2ip} proto esp "
                 f"spi {spi_1to2} mode {mode} {sa_auth} {sa_enc} "
-                f"{esp_args} {eflags} if_id 55 reqid {reqid_1to2} dir {direction} "
+                f"{eargs} {eflags} if_id 55 reqid {reqid_1to2} dir {direction} "
             )
             + iptfs_opts_filter_dir(direction, iptfs_opts)
         )
         direction = "in" if r == r1 else "out"
         eflags = esp_flags_filter_dir(direction, esp_flags)
-        esp_args = "replay-window 128" if direction == "in" else ""
+        eargs = esp_args_filter_dir(direction, esp_args)
         repl.cmd_raises(
             (
                 f"ip xfrm state add src {r2ip} dst {r1ip} proto esp "
                 f"spi {spi_2to1} mode {mode} {sa_auth} {sa_enc} "
-                f"{esp_args} {eflags} if_id 55 reqid {reqid_2to1} dir {direction} "
+                f"{eargs} {eflags} if_id 55 reqid {reqid_2to1} dir {direction} "
             )
             + iptfs_opts_filter_dir(direction, iptfs_opts)
         )
diff --git a/tests/flood/test_flood.py b/tests/flood/test_flood.py
index 738312b..7b35726 100644
--- a/tests/flood/test_flood.py
+++ b/tests/flood/test_flood.py
@@ -78,6 +78,7 @@ async def test_policy_tun_agg(unet, astepf, tun_ipv6):
     await setup_policy_tun(
         unet,
         mode="iptfs",
+        esp_args="replay-window 128",
         iptfs_opts=f"init-delay {INIT_DELAY}",
         ipv6=True,
         tun_ipv6=tun_ipv6,
@@ -95,6 +96,7 @@ async def test_routed_tun_agg(unet, astepf, tun_ipv6):
     await setup_routed_tun(
         unet,
         mode="iptfs",
+        esp_args="replay-window 128",
         esp_flags="esn",
         iptfs_opts=f"init-delay {INIT_DELAY}",
         ipv6=True,