Re: Refresh of DNS servers

[Ralf Angeli <dev.null@iwi.uni-sb.de>]

* Kai Grossjohann (2004-02-02) writes:

> Ralf Angeli <dev.null@iwi.uni-sb.de> writes:
>
>> Gnus seems to cache DNS servers.  This is fine as long as the same DNS
>> servers are used all the time.  But if Gnus is used on a notebook with
>> changing PPP and Ethernet connections it can become a problem.  I am
>> in such a situation and have to restart Gnus whenever I am switching
>> to one or the other connection type.  If Gnus is not restarted it uses
>> the old DNS servers.
>
> Does it really do that?  I'd be surprised.

Here it does.  I tested it the following way:

1. Unplugged the Ethernet cable of the notebook (and drove home (c;)

2. Disabled the Ethernet interface with ‘ifconfig eth0 down’

3. Put in the following iptables rule to log the DNS traffic:

   iptables -A OUTPUT -o ppp0 -p udp --dport 53 -j LOG

4. Started the PPP interface by dialing a provider

5. Tried to refresh Groups by hitting ‘g’ in the group buffer

The result showing up in /var/log/messages was a query to the name
server I originally configured for the eth0 interface and not the name
servers for the dial-up connection.

> Maybe it's sufficient to hit ^ to go to the servers buffer, then use D
> to deny the servers, then C to close them, then O to open them.  Does
> this work?  (I think one of the steps D, C, O is unnecessary, but I
> don't know which one.)

I tried it and I am afraid that it did not work.

-- 
Ralf