167832 - IMAP Server Refuses Connection after change in LAN

Status: RESOLVED DUPLICATE of bug 473483

(MailNews Core :: Networking: IMAP, defect)

Description

[Adrian Gropper]

In Mozilla 1.1 under XP, I use a wireless laptop on separate LANs at home and at
work. When I move from one to another, Mozilla's Web server continues to work
but Mozilla's IMAP Mail client fails to check mail and reports a conection
refusal on the part of the IMAP server. Restarting Mail alone does not fix the
problem but restarting Mozilla completely allows mail to function normally until
I change LANs again.

This used to work in Netscape 6 and Mozilla 1.0.

Thanks,

Adrian

Comment 1

[Russell Odom]

I have a laptop which I use at work and home, and use IMAP to read my e-mail. At
work, the internal DNS server resolves the name (imap.X.com) to the internal IP
address of the machine (192.168.X.X), and on my home LAN the DNS entry (from our
public-facing DNS server) is set up correctly with the external IP address of
the machine (62.188.X.X). (Adrian, is this similar to your own setup?)

If I start Mozilla at work and connect to the mail server, then hibernate the
laptop and take it home, and try to read my e-mail from home, Mozilla cannot
connect to the server - after a short delay I get 'Connection refused'.
Restarting Mozilla (whole app, not just Mail & News) cures the problem. I'm
assuming that the IP address of the mail server is not being refreshed when I
swap networks.

Doing...
ipconfig /release
ipconfig /renew
ipconfig /flushdns
...makes no difference, although other programs seem to notice the change. I
haven't tried it with the browser comonent on websites with similar DNS setups
(I use Naviscope as a proxy server, and it picks up the change), but will do so
when I next get the chance.

This is on Mozilla 1.3a (2002121215).

Comment 2

[Russell Odom]

Related, probably same root cause: 188353

Comment 3

[benc]

can you reproduce this easily?

if so, please include the ipconfig output before and after you renew your address.

Put the results here and I'll look at them.

Comment 4

[Andre Santos]

Finally I got some spare time to give some more feedback on this.
I am using Mozilla 1.4 on Windows XP, but have been living with this bug for
ages. It was the same under Win2000 and probably other OSs before that,
but I am not sure.

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4) Gecko/20030624

Very easy to reproduce, as described in the other mails, but here it
is again:
1) arrive at work. The computer gets its DHCP from the network (below).
  I get DNS names for my local www server, imap server etc. all with
  local, private IP numbers.

C:\Documents and Settings\alms>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
        Connection-specific DNS Suffix  . : cin.ufpe.br
        IP Address. . . . . . . . . . . . : 172.17.100.22
        Subnet Mask . . . . . . . . . . . : 255.255.0.0
        Default Gateway . . . . . . . . . : 172.17.33.254

C:\Documents and Settings\alms>nslookup www.cin.ufpe.br
Server:  cinns.cin.ufpe.br
Address:  172.17.33.111
Name:    palmares.cin.ufpe.br
Address:  172.17.33.44
Aliases:  www.cin.ufpe.br

C:\Documents and Settings\alms>nslookup imap.cin.ufpe.br
Server:  cinns.cin.ufpe.br
Address:  172.17.33.111
Name:    nazare.cin.ufpe.br
Address:  172.17.33.110
Aliases:  imap.cin.ufpe.br

2) hibernate (I believe this is not related to hibernation),
   go home, connect at home (or at any external site), where I
   (automatically) get another DHCP number and use de same 
   names for accessing my univeristy www site and
   imap server, *but* the IPs are now different (since my
   servers now are acessed through NAT):
C:\Documents and Settings\alms>ipconfig
Windows IP Configuration
Ethernet adapter Local Area Connection:
        Connection-specific DNS Suffix  . :
        IP Address. . . . . . . . . . . . : 192.168.0.164
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.0.1

C:\Documents and Settings\alms>nslookup www.cin.ufpe.br
Server:  UnKnown
Address:  192.168.0.1
Non-authoritative answer:
Name:    palmares.cin.ufpe.br
Address:  150.161.2.2
Aliases:  www.cin.ufpe.br

C:\Documents and Settings\alms>nslookup imap.cin.ufpe.br
Server:  UnKnown
Address:  192.168.0.1
Non-authoritative answer:
Name:    nazare.cin.ufpe.br
Address:  150.161.2.100
Aliases:  imap.cin.ufpe.br

3) in (2) I have not exited Mozilla, which was started at work.
   If I try to access my www.cin.ufpe.br site I get an
Alert pop-up:
The operation timed out when attempting to contact www.cin.ufpe.br

   If I try to get my e-mail from imap.cin.ufpe.br I get an
Alert pop-up:
Connetion to server imap.cin.ufpe.br timed out.

I suspect I would get the same errrors for pop ou smtp, but haven't
tried these.

Clearly there is a DNS cache somewhere in Mozilla that, on getting these
time out errors, should *try* to get a new DNS name for the host 
*before* giving up and returning the Alert message. If the DNS resolves
to the same IP it should give the error message, but otherwise it
should update (or flush) the cache and try again. Obviously whoever
implements this has to be careful for not creating a loop (e.g. if
this behaviour is used for hosts that map to multiple IP addresses in
a DNS lookup it should try contacting the sequence of hosts, but stop
after trying them all).

Closing Mozilla windows (mail or browser) doesn't help, unless all of
them are closed (that is, unless you exit from Mozilla). That is
the workaround, I always exit Mozilla completely when I get at home or
at work.

The bug is not related to changing IP numbers (since if I go to two different
places outside my firewall and get different DHCP numbers I do not need
to exit Mozilla).

Hope you manage to fix this. That forbids me from using the quick startup
option (I forgot the name) for Mozilla, since it makes killing and
restating Mozilla a bit harder.

Changing subjects, I never got the option of using the multiple SMTP servers
(to be tried in sequence) working, It always tries only one of them (that
is, when the first fails it doesn't try to send the e-mail through the next server).
This is probably a different bug, though.

Thanks,

Andre.

Comment 5

[Wayne Mery (:wsmwk)]

probably fixed by 473483. If you find otherwise, please reopen the bug.