232335 - DNS cache does not expire

Status: RESOLVED WORKSFORME

(Core :: Networking, defect)

Description

[Tom Whipple]

User-Agent:       
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031007

This bug is being opened as requested in the response to this comment:
http://bugzilla.mozilla.org/show_bug.cgi?id=198594#c11

When I take my laptop from one network to another, the DNS information is not
valid. On my home network, my home page resolves to a private IP address. When I
wake my laptop up on another network and press <alt-home>, Mozilla still
attempts to contact the IP address it found while connected to the previous
network. This continues to happen untill Mozilla is restarted.

This could be a security concern if the owner of the IP address on the second
network knew what I was expecting to see, though the chances of that are
admittedly remote.

Reproducible: Always
Steps to Reproduce:
See notes in the description.

Actual Results:  
Mozilla appears to hold DNS information indefinately.

Expected Results:  
The cache chould be emptied if the client's IP address changes. (Usually this
will happen from DHCP, but not necessarily.)

Comment 1

[Mihail Daskalov]

I'm sure this is duplicate of some other but could not determine which one.

Just do a search for DNS cache and you'll find several entries.

The workaround for your problem is to click Offline, then Online icon, and it
will be OK.

HTH,
Mihail Daskalov

Comment 2

[Mihail Daskalov]

or maybe an auto-offline should be done if possible when subnet change is detected.

Maybe this is what this bug is for. Sorry if I don't understand it.

I think that if a user unplugs his computer from a network, and then plugs it
again into some network they should put Mozilla in 'Offline' status themselves.
And then after connecting the laptop to the network again to put it in 'Online'
status.


But others could argue this should be done automatically. I think it would be
hard to implement such a functionality, especial how to detect network interface
is down/up. And what should happen if a machine has several network card ?!??

Comment 3

[Tom Whipple]

Please review comments 11 and 12 in bug 198594. 'benc' states "The cache expires
by default after 60 seconds.", which is clearly not happening. The same
individual requested a new bug, which, after searching bugs about DNS, I opened.

Weather or not Mozilla detects the network change is trivial in my opinion. It
would be nice, but if the DNS cache worked as I just indicated, the problem
becomes largely moot.

Comment 4

[Darin Fisher]

please make sure you have tested mozilla 1.6.  our host resolver was rewritten
for 1.6, and the rewrite included changing the DNS cache logic.  it should not
be caching DNS results for more than a minute (by default).

since it looks like this bug was reported against 1.5, i'm going to go on the
assumption that this bug is now WORKSFORME.  please reopen the bug if the
problem persists with 1.6.