error logs related to security server (10.0.0.235) as below:
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:52131 has ident: 27752 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:52131 has ident: 27753 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:52131 has ident: 27754 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:23540 has ident: 27755 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:52927 has ident: 27756 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:22059 has ident: 27757 flags:0x2 and 3 fragments
*Nov 19 15:51:23: %IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/1.10 - datagram 4026 bytes is too big. UDP packet 10.0.0.235:53 -> 64.31.29.30:50268 has ident: 27758 flags:0x2 and 3 fragments
output of "netstat -a" on security server (version 5.0.0) did shows ws_TunnelService.exe opened port 53