linux下上网老掉线，如何解决？

freshman36284

我用锐捷提供的认证客户端xrgsu，局域网接入internet,过程如下：
linux:/usr/bin # ./xrgsu -a
XRGSupplicant 1.0.1
RuiJie Network CopyRight 2004
Please input your user name:
Please input your password:
Use DHCP,1-Use,0-UnUse(Default: 0):
Use default auth parameter,0-Use 1-UnUse(Default: 0):1
Please input Eap-start Timeout(Default: 30s):
please input Eap-response Timeout(Default: 30s):
please input Eap-packet resend Time(Default: 3):
Use Red-Giant private MAC? 1-Use,0-UnUse(Default: 1):0
Searching server...
Connecting server...
Authenticating...
Authenticate SUCCESSFULLY!
Please input 'unauth' to LogOff:

Detect Proxy Server!Err = 4
xrgsu exit!
但登陆上以后，几分钟就掉线如上，在终端上每次这样登陆挺麻烦的，不知有没有好的解决办法
请高手指点