[arch-general] Switching between Internet connections

[Leonid Isaev]

On Fri, 07 Dec 2012 13:02:12 +0530
Sudaraka Wijesinghe <sudaraka.wijesinghe at gmail.com> wrote:

> Hello,
> 
> My laptop is connected to a LAN with Internet connection and it gets the
> IP stuff (address, routing, dns) via dhcp using the default systemd
> scripts on boot. I also have a 3G modem (USB) which I have created the
> ppp scripts to connect based on the Wiki article
> https://wiki.archlinux.org/index.php/3G_and_GPRS_modems_with_pppd
> 
> Both connections work fine, except after switching to modem from LAN
> some applications (pidgin, xchat, ect. which were running) still uses
> the DNS nameserver from previous connection (LAN) meaning they still
> trying to send DNS queries to LAN router (which is not reachable at that
> time). This gets fixed after that application is closed and reopened.
> 
> Is this behavior normal or a bug?

I think it is normal. If you suspect DNS is the problem, just use a static
resolv.conf with google/comodo dns nameservers (add "nohook resolv.conf"
to /etc/dhcpcd.conf to forbid dhcpcd to touch the file).

> 
> Thanks.
> 
> P.S.
> 
> To disconnect/connect from LAN I either use:
> > # systemctl stop dhcpcd at wlan0
> > # systemctl start dhcpcd at wlan0
> or
> > # dhcpcd -k wlan0
> > # dhcpcd wlan0
> 
> To disconnect/connect I use poff/pon commands and the scripts are setup
> exactly as described on the Wiki.
> 
> 

So, you become root everytime you change network? If you need this kind
of dynamic connectivity, you'll be much better off using networkmanager...

-- 
Leonid Isaev
GnuPG key: 0x164B5A6D
Fingerprint: C0DF 20D0 C075 C3F1 E1BE  775A A7AE F6CB 164B 5A6D
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