cannot connect to the Internet at the same time

[WXYZ-2]

hello guys,
I have meet a strange problem.
my host system is ubuntu ,and i install a guest system :xp in my virtualbox. but the problem is when i turn on my guest system(xp) ,the host system will not able to connect to the internet.
what's worse, at this moment ,my host system will fail to connect to internet. the eth0 will not work for several i use the "ifconfig" and get strange result

Code: Select all

eth0      Link encap:Ethernet  HWaddr 00:1d:60:75:4e:34  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:3276869 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2421729 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:2713440734 (2.5 GB)  TX bytes:204001871 (194.5 MB) 
          Interrupt:222 Base address:0x6000 

eth0:avahi Link encap:Ethernet  HWaddr 00:1d:60:75:4e:34  
          inet addr:169.254.4.121  Bcast:169.254.255.255  Mask:255.255.0.0
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          Interrupt:222 Base address:0x6000 

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:4819 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4819 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:269963 (263.6 KB)  TX bytes:269963 (263.6 KB) 

i was so confused with the result . i just have one net card eth0 ,but the result has the "eth0:avahi" what is the meaning?

did anyone meet this question before?
Can anybody help?
thanks for reading this

PS: our school use a client software connect to the internet

[Sasquatch]

eth0:avahi is an alias made by the Avahi daemon. As you can see, you have an APIPA address (169.254.x.y), which is assigned by that daemon if no DHCP address can be obtained.

For more help, please post your system setup, the VM settings etc. See the Forum Posting Guide for more information on what we need.

[WXYZ-2]

eth0:avahi is an alias made by the Avahi daemon. As you can see, you have an APIPA address (169.254.x.y), which is assigned by that daemon if no DHCP address can be obtained.

For more help, please post your system setup, the VM settings etc. See the Forum Posting Guide for more information on what we need.

Well.My host OS is Hardy Heron 8.04.2 desktop,Vbox 2.1.4 NAT guest system is xp sp3 + 2.1.4 guest additions

[WXYZ-2]

I have solved this problem.
Just comment the Host OS snmp services in the /etc/services file

[Sasquatch]

That shouldn't be done actually. If you need some sort of application to be able to access the internet, you might be better of using Host Interface and configure the Guest to use the same kind of program. For connection to MS ISA proxy servers, ntlmaps should do it.