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TOPIC: Destination net unreachable issue

Destination net unreachable issue 12 years 9 months ago #15544

  • Skodje
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I am attempting to ping from a comuter on one subnet to a device on another and I keep getting 6 destination net unreachable reply's and then one request timed out from the gateway of the workstation that I am pinging from. (the gateway is a subinterface on our main router that is configured to provide DHCP addresses to PC's that are attached to it.)

If I go on the router and set up an extended ping from the actual subinterface that I am behind, I get a reply. When I choose an address from behind the gateway, I can't reach the destination device.

Both subnets are on the same main router so to the best of my knowledge, a static route shouldn't be necessary. These networks should be able to see each other. As well, I have removed all Access lists from the subinterfaces and still get the same result.

I've had a continuous ping running for an hour and keep getting 6 destination net unreachable and 1 request times out.

Does anyone have any ideas regarding what may be causing this issue?


Problem 12 years 9 months ago #15552

Destination net unreachable is the router telling you that it doesn't know how to reach the network the ping packets are intended for. This would suggest that the router has no routing information for that interface (it probably works when you do it from the router itself because then you are inside the router's OS rather than coming in from outside through a physical port). If you have a routing protocol running on the router then that should automatically pick up the interfaces (e.g. RIP, OSPF). Check that it is enabled on the port you are having problems with. If you don't have a routing protocol in operation then you probably will need static routes.
Let us know the make and model of your router and I'm sure someone will be able to provide more specific advice

Re: Destination net unreachable issue 12 years 8 months ago #16229

im having a similar problem, except mine only pertains to a few machines in my network...

i have a netopia R series router, and i have about 6 computers in my LAN... and most of them work fine accessing outside of the network, but 2 of them wont let me... one actually did work fine and just stopped for some reason...

with these 2 machines i can get onto the local network, access other computers on the network, etc. but i cant go outside of the network to get on the internet... and if i try to ping anything outside of the network i get the destination net unreachable error... also if i try to ping say 444.233.444.444, it replies with my routers internal IP ( then says destination net unreachable...

i do not know why this is happening on only 2 of the computers in my network... can anyone help?

Re: Destination net unreachable issue 12 years 8 months ago #16262

Do your PCs have fixed IP addresses or do they get their details via DHCP from the router? In either case check that the subnet mask on all the PCs and on the router are the same. Also worth checking that the two problem PCs are pointing to the same default gateway address (should be your router) as the others and that they don't have any other routes defined (type 'route print' at a command prompt)

Re: Destination net unreachable issue 12 years 8 months ago #16319

  • Dove
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by default Router Will not forward the traffic from one network to another even if its Physical / Sub interface.

To route the traffice from one network to another routing should be enabled even if these networks are connected in the same router.

The static routing is must on this setup to work out.


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