there must be a loop in my network

[htkiet_globaleis]

dear sir,

could you please help me make clear the problem i have?

the network was operating well before adding a connection between SW-02 & SW-04. I could not ping from 192.168.1.100 to .110 & .203( disappeared in the diagram) since there has been that link. if i removed the link out and cleared arp table in switches, then the network become good.

I checked the arp table in SW-01&02 that there was a map of ip addresses and the Mac add of the pix' dmz interface.

i am looking forward your reply.

Kiet

[mmellet]

I think there is some problem with the STP configuration on the newly added switch due to which there may be loops.

To confirm that the problem is with the loops you could try giving a traceroute and check where the packet drops when you trace from 192.168.1.100 to say 192.168.1.110. If there are loops check the VTP and STP configuration on the new switch. Sometimes what can happen is that the new switch may have some old VTP config because of which it can become a "VTP server" and advertise the wrong routes. This can happen if the VTP config is not erased before it is added to the production network. You could check on both STP and VTP configuration. This could be the root cause of the problem

[htkiet_globaleis]

Hi mmellet,

thanks so much for you message.

I checked all as you suggested. There is no problem with them.

the problem is that the network was operating before i added the new switch into the network. the problem did not occured right after adding the new SW. it occured one week after the new SW was added.

I wonder whether the problem is by pix or not.

regards,

Kiet