Do you have DNT enabled on the browser that does not track?
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Thanks for your quick response.
And my machine (scdev2) has the setting "Do Not track" checked in Chrome but I can still see marketo cookie getting set.
I think the problem may be because of IP address, it should be some local host name..I'll give that a try
DNT has no direct effect on whether cookies can/will be set and sent to servers. What's important is whether the remote server uses the cookie for tracking. When a server sees the DNT header, it is supposed to discard non-critical info about the session (which is more than just cookies, since a first-party server can see all your network requests even with cookies disabled).
Your problem (as you figured out) is setting cookies when using an IP address as your hostname. You'd need to set Munchkin's domainLevel to 4 for this to work.