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DHCP subnet mask is changing by itself

I bought a PIX 515E on 8-2-06. The device has been performing fine, I am also running DHCP off this device.

Yesterday I had 2 PCs not able to access network or internet. It was discovered that they had a new subnet mask of 199.x.x.x vice I did a release and renew and they started working again.

This morning, I have had 6 more PCs do the same thing with the same subnet mask of 199.x.x.x UNTIL a few minutes ago.

I just got a PC with a subnet mask of

In each case, a release and renew solved the problem.

I only have one device handling my DHCP. Each time there was an issue the IPCONFIG /ALL showed that the DHCP server was the PIX 515E - which that is correct.

I am running Norton Antivirus Corporate Ed which handles spyware, etc.

Does anyone have a clue as to what is going on? Is my PIX 515E going bad, dropping packets, etc.?

Please help.

I'm very perplexed.


Re: DHCP subnet mask is changing by itself

So am I. :-)

Well can you capture DHCP packets on one of the PCs in the subnet (f.e. with WinShark, aka Ethereal)? Would be interesting to see, if the PIX is sending nonsense or the PCs are to be blamed.

Regards, Martin

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