Help with routing table (different ranges in same LAN)

N

NEODARK

Gawd
Joined
Aug 10, 2004
Messages
1,002
Hey guys,

Need some help with routing tables to allow connectivity between workstations in different IP ranges within the same LAN... Or maybe an alternative to the current model I'm using.

I've attached a picture below to try and make it easier to understand. The main reason for this setup is to limit bandwidth for workstations under the PC that is doing the ICS, via net limiter. (Don't want to go the route of IPcop, etc.. And My router cannot do bandwidth limitation per IP, but it allows me to create routing table entries, etc.)

Anyway... The server, which is doing ICS has two nics. 192.168.3.2 which is used to connect to the router and it's doing the ICS with a secondary nic, which is: 192.168.137.1

The setup works and all PC's can get to shares on the server. However, workstations in the 192.168.3.x range (PC1, PC2 & PC3) cannot communicate with workstations in the 192.168.137.x range (pc4, pc5 & pc6).

I've added a custom user entry to my routing table which allows me to access the router (192.168.3.1) from a PC in the 192.168.137.x range, but I still cannot access resources on PCs across ranges, what am I missing?

The question is... How can I make these two different ranges communicate and reach each other?

Thanks...

59760462.gif


neto.gif
 
Well, you need gateway addresses, but what router are you using?

for the 192.168.137.0 network, you need to put in the default gateway (interface the router has in the network) such as 192.168.137.0 and for the 192.168.3.0 network the default gateway needs to be 192.168.3.1

This assumes that you have a router with two physical interfaces or virtual interfaces, one in each subnet.
 
From re-reading your post it looks like you need to add an interface on the router to the 192.168.137.x subnet, then use that as the default gateway for the subnet, and update the default gateway in your router for both subnets to the default gateways.
 
^You need to add a gateway, but,

I thought ICS could only use the 192.168.0.0/24 subnet. What OS are you running? Were you doing some reg editing?
 
Thanks for the suggestions.

I tried adding the gateway for the PC's after the switch, under ICS... but either I didn't set it up correctly or it didn't do the trick. Also, no registry tweaking. All Windows 7 workstations

PS: In the drawing above, where it says "Router" that is the gateway @ 192.168.3.1
 
Your route for the 137 network is wrong, currently it looks like it's configured as a directly connected route, which it's not. This will interfere with return-path traffic back towards the 137 network as the router will be attempting to resolve host mac addresses on the local link rather than forwarding the packets to the 3.2 gateway.

It needs to look like this

Dest IP 192.168.137.0
Netmask 255.255.255.0
Gateway 192.168.3.2

Cheers
 
Lightworker said:
It needs to look like this

Dest IP 192.168.137.0
Netmask 255.255.255.0
Gateway 192.168.3.2

Cheers
Click to expand...

So, in short... I need to change NIC2 on SERVER, correct?

Thanks for your help :D

PS: Unfortunately... The above didn't work. I was not able to set an IP ending in 0 for that NIC.
 
Last edited:
No that's not the correct change. The server should be fine, but you need to modify the route on your router listed here:

59760462.gif


Change it from
Code: 
Destination IP          Netmask                 Gateway
192.168.137.0          255.255.255.0          0.0.0.0

To:
Code: 
Destination IP          Netmask                 Gateway  
192.168.137.0          255.255.255.0          192.168.3.2

You never answered the question regarding the type of router it is, but I'm going to assume that since it's a "User" route and not a system route that it is a static route that you manually entered.
 
oops, didn't understand your question until I re-read it. Yeah, it's a route I had manually created :)
 
Last edited:
By the way,

What gateway should PC 4-6 be using? (I assume 192.168.173.1)

I edited the route on the router to your suggestion, and I'm still unable to view/ping/access PC1 - 3 from PC 4-6 or vice versa.

Thanks again :)
 
If you could post the routing table from both your router and the server that would be helpful.

This entire thing will be dependent on your ICS box's configuration as well, proper default route, nat, etc
 
Sure, I hope this is what you need: (The two NICs on SERVER & the routing table from the router)

81832328.png



PS: If I enter the gateway 192.168.3.2 on the adapter on right... I receive the warning below. Either way, blank or with the gateway IP... The PC's with the question marks on the original graph are still un-pingable between each other.

warningo.png


And again, thanks for your help :)
 
Last edited:
It just dawned on me that ICS has nat enabled, your 192.168.3.x users won't be able to hit 192.168.137.x users unless you config port forwarding on that right hand dialog in the screenshot you posted.

Can you PC's on the 192.168.137.x network reach the internet? Ping 192.168.3.1? Ping 192.168.3.2?
 
Yes, 137 can reach the net... And, because of the user rule also reach the gateway (router) configuration page. But, "3" cannot anything on "137" or viceversa.

I think I should stop complicating things and maybe just add a switch from that 2nd NIC on server and connect directly to the PC I need to via the 2nd nic. 2 wires, but... I think that resolves the issue.
 
Smells like nat+routing to me, I'm not familiar with that router though so I'm not sure what else to tell ya =/
 
Post a "route print" from one of the PCs (1-3)
Post another "route print" from one of the PCs (4-6)

Traceroute from one of the PCs (1-3) to 192.168.137.4
Traceroute from one of the PCs (4-6) to 192.168.3.4

(If you can, run wireshark and filter on ICMP on the receiver of the traceroute to better troubleshoot if it's the source or return route)
 
Ah wireshark... It's been a while. Last I used it was Ethereal. I'll give that a go tomorrow and post results. Thanks guys :)
 
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