4.5 second delay due to netbios lookups

[Doug Stalker]

I have an install of MySQL 5.0.67 on a Windows 2003 machine, with an internal IP of 192.168.1.1 and an external IP of 222.222.222.222.

I have a client system, Windows Vasta, on a different internal subnet with IP address 10.1.1.1.


If this client uses the IP 222.222.222.222 to connect to the server the packets go out to the internet and back to the server. In this scenario everything works fine.

If the client uses the IP 192.168.1.1 to connect to the server the traffic goes through an internal link, and there is a 4.5 second dely whenever establishing a connecion - both for the MySQL GUI tools starting up and the mysql command line. This delay is only for the initial connection - once connected it all works fine.

Running a packet sniffer on the client shows that when the IP 192.168.1.1 is used to connect to the server the server sends out 3 NBNS packets to do a name query of some sort, spaced 1.5 seconds apart. Only after these packets have "timed out" does it continue to send Mysql traffic. There is no response from the client to these packets. The Wireshark summary for the packets is "Name Query NBSTAT *<00><00><00><00><00><00><00><00><00><00><00><00><00><00><00>"



In Wireshark I see the TCP SYN/ACK, then the netbios packets, then the MySQL server greeting. When the external IP is used the connection goes straight from being established to MySQL connumications.


How can I stop this additional netbios lookup from happening? And for bonus points, why does it not do this when the source IP address is on the internet instead of being a private IP (on a different subnet)?



Edited 1 time(s). Last edit at 03/04/2009 07:15PM by Doug Stalker.