"VboxNetNat.exe" Random crashes

[qidizi]

host OS:window 7; host some software:avast!; noteBook:lenovo k27,intel I3,RAM 8G,ssd 128G; host network:LAN,or LAN wifi; guest OS:centos 7; guest network:NAT network,forwarding port(tcp127.0.0.1:22 => 10.0.2.5:22,tcp127.0.0.1:80=>10.0.2.5:80;tcp127.0.0.1:3306 => 10.0.2.5:3306),interface:Intel Pro/1000 MT server (82545EM) mixed mode is disabled; vm virtualbox VER:4.3.23-98520/4.3.22(test both )

when testing,only this guest OS is runing! my email is :qidizi&qq.com If you are using a NAT(not NAT network), this problem will become more serious, see the following link:https://www.centos.org/forums/viewtopic.php?f=50&t=51112 If you use the "bridging model", this problem would not have arisen; Possible causes:postfix(http://www.postfix.org,Install on CentOS systems) is runing,and A large number of mail is being delivered;and the browser on the host(window on "k27"), constantly refresh a PHP page,the "nginx/php" on Centos;then "VboxNetNat.exe" Random crashes,But I cannot determine what operation caused crash;

[qidizi]

They are normal

[qidizi]

when crash;can ping www.qq.com;but forward port is suspended,ssh/80 be loading...until close the crash message window;

[qidizi]

but some time do not show this crash window,when it crashed;

[qidizi]

after close the crash message window,all "vboxnetnat.exe" is crash;