207792 - Proxy: IP address is cached, becoming stale on network change

Status: RESOLVED EXPIRED

(Core :: Networking, defect)

Description

[Marius Mikucionis]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030529
Build Identifier: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030529

I connect to internet at home and in office. The ISP is the same and the proxy
server name localy is the same (wwwproxy), but the IP resolved is different
(since networks are different). While travelling from home to office I do
suspend and when I wake the system up, mozilla does not re-lookup for new proxy
address and the old proxy cannot be reached.
The temporary resolution is to restart browser (loose many todays links) or to
go and edit proxy preferences manually (which is very anoying to do twice a day).
I know that it is a good optimization to cache the proxy address, but I also
want an easy resolution when something changes in the network (proxy is quickly
substituted by another machine and DNS resolution is changed dynamically).
I think it would wise for mozilla to do a DNS re-lookup when the old proxy
cannot be reached, or do that when e.g. user presses Reload button holding Ctrl
or Shift key.
I don't think that I am the only one with this problem, other programs like xmms
and licq do not have such problem :)

Reproducible: Always

Steps to Reproduce:
1. start browser with proxy being set up to e.g. name "wwwproxy"
2. browse internet a bit
3. shutdown the proxy service or migrate to another network
4. start proxy on another machine and change the DNS "wwwproxy" resolution to
that machine :)
5. try to refresh any of the pages in the browser
I think the problem is pretty obvious not to do these steps ;)
Actual Results:  
Internet becomes unreachable, i.e. the old proxy service cannot be reached and
the new one is not discovered.

Expected Results:  
Mozilla should refresh its proxy IP resolution each time the current proxy
server cannot be reached OR do this at a user request, e.g. when the Reload
button is pressed while holding the Ctrl or Shift key.

I have been experiencing this problem all the time - I think nearly all Mozilla
and Netscape versions have this problem.
And now I got tired of it...

Comment 1

[Jo Hermans]

That's because of bug 162871.

Workaround: click on the connection-icon (lower right) to go offline, and online
again. That will clear the DNS-cache.

*** This bug has been marked as a duplicate of 162871 ***

Comment 2

[benc]

VERIFIED/dupe.

You can tap the offline/online button to reset the cached DNS entry.
Please reopen if this does not work.

Comment 3

[Marius Mikucionis]

Unfortunately the offline-online workaround does not work.
Browser still remembers the old wwwproxy machine.
Maybe the problem is in some kind DNS cache?
I.e. to be precise, I specify proxy server as "wwwproxy", which resolves
as wwwproxy.aabh.auc.dk at home and in the office this must resolve as
wwwproxy.cs.auc.dk, but the browser still looks for wwwproxy.aabh.auc.dk which
denies its service when I am in the office.
And at home if wwwproxy.aabh.auc.dk goes down the wwwproxy resolution goes to
some another machine.
I verified this problem with xmms radio streaming - it does not have this
problem, which concludes that this DNS caching is not somewhere in operating
system :-/
Any other ideas?

Comment 4

[Olivier Cahagne]

see also bug 210885.

*** This bug has been marked as a duplicate of 109313 ***

Comment 5

[benc]

VERIFIED/dupe.

Comment 6

[benc]

REOPEN:

Here's the question I want to pose to Darin:

"Should proxy servers have different cache behavior that regular browser traffic?"

This bug contains the best case I can find for this feature. (In the DNS
re-write, there are some hints that there might be support for calling the DNS
service with a bypass-cache flag).

Based on what I have heard here, my opinion would be no. In a normal session,
the proxy IP would not change, and if it did, I don't see why this would behave
any differently than normal web traffic. I don't know DNS cache tries to refresh
its records if the connection fails, but that would be a design decision that is
not specific to proxy server handling.

What is needed in this case is clear documentation of DNS cache behavior, as
well as support for manual reseting of the DNS cache. (This feature, bug 192798,
has been erratic and undocumented for some time, but I think Darin has decided
to hammer it permanently into place).

In the long run, we need to think about supporting network changes more
robustly, bug 223908.

Comment 7

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

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Comment 8

[Gervase Markham [:gerv]]

This bug has been automatically resolved after a period of inactivity (see above
comment). If anyone thinks this is incorrect, they should feel free to reopen it.