[lwip-users] DNS using Wired interface and PPP

[Sergey A. Borshch]

Hello everybody.

My system has two network interfaces: main is wired Ethernet and backup is 
cellular modem using PPPoS. I want to choose which interface to use by 
netifapi_netif_set_default().

The problem I expect that both interfaces got DNS servers addresses from 
providers. It is possible that each of interface is connected to each own 
subnetwork and each provider has it's own DNS servers in their subnetworks not 
accessible from outside of subnetwork. It means that when I use wired Ethernet 
interface I should use DNS servers supplied by Internet provider via DHCP and 
using cellular modem interface I should use DNS severs supplied by cellular 
operator via IPCP. What is correct way to do do such scenario in lwIP?

As far as I understood lwIP architecture, it uses two global (system-wide) DNS 
addresses (by default) and each interface overwrites them after getting new 
values by DHCP/IPCP. So used DNS addresses depends on which interface got their 
DNS addresses last.


--
Regards,
  Sergey A. Borshch            mailto: address@hidden
    SB ELDI ltd. Riga, Latvia