diff --git a/clib/tcpdump_helper.py b/clib/tcpdump_helper.py
index 03c6be71c3..7dea4ce81a 100644
--- a/clib/tcpdump_helper.py
+++ b/clib/tcpdump_helper.py
@@ -31,6 +31,7 @@ def __init__(self, tcpdump_host, tcpdump_filter, funcs=None,
             self.intf_name = self.intf_name.split('.')[0]
 
         tcpdump_flags = vflags
+        tcpdump_flags += ' -Z root'
         tcpdump_flags += ' -c %u' % packets if packets else ''
         tcpdump_flags += ' -w %s' % pcap_out if pcap_out else ''
         tcpdump_cmd = 'tcpdump -i %s %s --immediate-mode -e -n -U %s' % (