Depends how many of them you get.
Basicly there is no entry in the stateful firewall table of an initial SYN request so the Firewall is refusing the connection.
Cause:
a.) Asymetric routing
b.) timout issues
http://www.cisco.com/en/US/docs/security/asa/asa72/system/message/logmsgs.html#wp1279822
Error Message %PIX|ASA-6-106015: Deny TCP (no connection) from IP_address/port to
IP_address/port flags tcp_flags on interface interface_name.
Explanation The security appliance discarded a TCP packet that has no associated connection in the security appliance connection table. The security appliance looks for a SYN flag in the packet, which indicates a request to establish a new connection. If the SYN flag is not set, and there is not an existing connection, the security appliance discards the packet.
Recommended Action None required unless the security appliance receives a large volume of these invalid TCP packets. If this is the case, trace the packets to the source and determine the reason these packets were sent.
sincerely
Patrick
