Analyse with ethereal

[nymus]

I'm using ethereal to analyse the network.

There're too many TCP Bad checksum
1. between my PC and unix servers (checksum: 0x6660 [incorrect, should be 0xa6e2]
2. between my PC and other servers (windows, novell) checksum: 0x6644 [incorrect, should be 0xf50a]

There're too many NBNS and BOOTP/DHCP Malformed Packet(Exception occured)
1. multicast (224.0.0.2) from switch [Illegal NetBIOS name]
2. multicast (224.0.0.2) from switch [BOOTP Unknown BOOTP message type (0)Malformed Packet]

1. Are there problems "acceptable" or not?
2. How to find if these problems come from my pc or from net?
3. Are there a software problem (Application layer) or TCP/IP stack problems, how to find them?
4. In which ways should I analyse to find solution?

Best regards
ns

 

[Frank4d]

This FAQ

http://www.ethereal.com/faq.html#q5.14

may help answer you TCP Bad checksum question.

 

[nymus]

Thanks Frank4d for your answers about TCP Bad checksum
Any ideas about the other messages?

regards
ns