search

arduino-libraries / Ethernet

Ethernet Library for Arduino
http://arduino.cc/
254 stars 257 forks source link

Default Gateway not working in Routed Network with Static IP's unless myDns used - DHCP works fine #156

Open per1234 opened 3 years ago

per1234 commented 3 years ago

Moved from https://github.com/arduino/Arduino/issues/4746 by @andysoondyba

Issue when trying to connect to devices behind different networks. This is not a home NAT'd setup. Two or more different networks connected with routers and default gateways.

Static IP settings don't establish a route/arp table when checking with Wireshark. If the exact same settings however are received from DHCP, all is OK.

The addition of myDns solves the issue. It doesn't matter what I set the DNS IP address to, it just needs it. My project however doesn't require any DNS services. After adding this is can see the route/arp requests exchange in Wireshark and the connection establishes.

What is myDns doing in the back ground to correct this action? From a comment on this topic in the forums and bug https://github.com/arduino/Arduino/issues/4616 it might be related to extra info that DHCP obtains that's not always being set when statically defining network setting.

When using DHCP and not declaring myDns the sketch will still work. I'm assuming the data is still being collected in the library's inner workings.

per1234 commented 3 years ago

From facchinm on 2016-03-23:

Hi andysoondyba.

Which shield are you using? IDE and Library version?

per1234 commented 3 years ago

From andysoondyba on 2016-03-23:

Hello, Freetronics ethermega with w5100. Arduino 1.6.7Ethernet version 1.1.1(read from library.properties)