Firefox cookie lesson

I ran into a problem caused by a internal site setting invalid cookies (ones with “@” as part of the cookie name) and tried to fix it by using the Firefox cookie manager to delete the offending cookie. This might have been OK, except that I’d also set Firefox to not allow a site for which I’d removed cookies to set cookies in the future.

And so removing the one errant cookie blocked all ibm.com sites from setting cookies — this had some unfortunate side effects (such as making it impossible to log into several internal sites). I couldn’t find any way to reverse this, either — not even running Firefox in safe mode helped.

So I resorted to rummaging through my profile directory and looking at any file which was human-readable. The last file I checked (of course!) was hostperm.1; that file had a line in it setting the “cookie” property of ibm.com to “2”. I deleted the line and my problems went away.

I will probably keep the Firefox setting to prohibit a site who’s cookies I’ve deleted from setting cookies in the future, but this posting will help me remember what to do if it causes me problems, too.

2 thoughts on “Firefox cookie lesson”

  1. I just had the same problem. The Ideas site, right? Have you reported their cookie nastiness to them? Have you reported the bug in Firefox?

  2. Yep, I have reported the cookie problem and they promised a fix, which they’ve delivered; now, instead of an “@” in the cookie name, they use an “!” But they didn’t delete the offending cookie, which I thought they’d do.

    I can’t describe what Firefox does as a bug, though — it works as it says it will if you have the “don’t allow cookies from a site if you delete a cookie from that site” box checked. And most of the time, when I delete a cookie (say the one from servedby.advertising.com), I really want the Firefox behavior. But when I *don’t* want it, it’s hard to figure out what happened.

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