Static route to fix IP address overlap.

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qyiet

454 posts

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#177756 13-Aug-2015 11:36

As you can tell from the title this is a hack job. The ideal solution would be to change the subnet of addresses at location 2.

Lets start with the Network Diagram https://i.imgur.com/lVyVzBt.png

What I want to do is add a jumpingsumo drone to a wifi network at location1 and the little bugger has an IP address you cannot change. However it has an IP address that should reside in location2 lan.

Can I add the IP address 192.168.1.2 to the location1 router on it's own interface and put a static route in to 192.168.1.1/32 to allow vlans 1, 2, and 3 to access the drone while still going to location2 lan for 192.168.1.3-254? Or is there a better way to do this?

Warning: reality may differ from above post

wasabi2k

2098 posts

Uber Geek

#1365499 13-Aug-2015 12:10

If you create a 192.168.1.x/24 interface on your router it will have a default connected route for that network created automatically.

As long as clients are using the router as their default gateway traffic for 192.168.1.1 will use the router interface to reach it.

Does the drone have a default gateway set back though? and do any of the apps rely on any ugly layer 2 broadcast stuff.

Note: How are you connecting your drone to that interface? Is it a separate physical network with wifi that it is connecting to?

qyiet

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#1365541 13-Aug-2015 13:17

wasabi2k: Does the drone have a default gateway set back though? and do any of the apps rely on any ugly layer 2 broadcast stuff.?

You can actually reconfig the drone how you like.. so I can add gateways etc without issue. The apps however all assume a static IP address. AFAIK none of them rely on layer2 stuff as they don't bother with discovery as they assume the drone will always be on the same IP.

wasabi2k: Note: How are you connecting your drone to that interface? Is it a separate physical network with wifi that it is connecting to?

I have a spare Ethernet port on the router, so I was going to rig that directly into a cheap wifi AP initially. The plan was to preconfigure the AP on another network then not worry about trying to get at the management interface.

so <location1router eth3 -> preconfigured wifi AP -> drone

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qyiet

454 posts

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#1365543 13-Aug-2015 13:21

wasabi2k: If you create a 192.168.1.x/24 interface on your router it will have a default connected route for that network created automatically.

As long as clients are using the router as their default gateway traffic for 192.168.1.1 will use the router interface to reach it.

Hrm.. this is overkill.. I still want them to talk to the location2 network for the majority of 192.168.1.x network. Possibly I need to just add a IP with a tiny subnet.. somewhere between /24 and /32.

Warning: reality may differ from above post

wasabi2k

2098 posts

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#1365544 13-Aug-2015 13:21

Sorry just re-read that.

To do it properly you would need to split the 192.168.1.x network out into two smaller subnets.

You can't have one host out on another segment, clients won't go to their gateway if an IP is local according to their subnet mask.

So you would have to reconfigure the existing 192.168.1.x network as well.

Clients will use their local route for their subnet over a static route.

qyiet

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#1365556 13-Aug-2015 13:39

wasabi2k: To do it properly you would need to split the 192.168.1.x network out into two smaller subnets.

Right, but if I don't care about vlan4(drone) and location2Lan ever talking to each other I might get away with adding 192.168.1.2/30* to an interface on location1 router. Then clients on vlan1,2 and 3 should connect to vlan4 when trying to get to IP address 192.168.1.1, and 192.168.1.2 but connect to location2 lan for IPs 192.168.1.3-192.168.3.254

*had to go lookup the subnetting to get a two IP subnet.

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wasabi2k

2098 posts

Uber Geek

#1365559 13-Aug-2015 13:42

Nope, you would have to change the subnet mask on the existing 192.168.1.x subnet interface (Location2), which would break comms with any clients on that network already with a standard /24.

Otherwise your router has a connected route for the /24, and a static route for the /32. I believe the connected route would take precedence (over the more specific /32)

Which may come down to your particular router's routing implementation, but I believe that's how it should work.

qyiet

454 posts

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#1365569 13-Aug-2015 13:50

wasabi2k: Which may come down to your particular router's routing implementation, but I believe that's how it should work.

Yeah, it would be a broken setup, with the router knowing two ways to go to get to the same IP. Damn. I really don't want to have to try and mess with stuff at location2.

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wasabi2k

2098 posts

Uber Geek

#1365577 13-Aug-2015 14:01

qyiet:
wasabi2k: Which may come down to your particular router's routing implementation, but I believe that's how it should work.

Yeah, it would be a broken setup, with the router knowing two ways to go to get to the same IP. Damn. I really don't want to have to try and mess with stuff at location2.

If you are clever about it you could try and change the location 2 subnet to include all the devices already in it (i.e. if they are all from .1-.50), then it wouldn't be too much of a major, they would pick up a new subnet mask when they renew.

Otherwise you can get really freaky and have your router NAT requests to 192.168.1.1 to a different IP that is on the drone.. but who knows.

roobarb

653 posts

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#1365590 13-Aug-2015 14:27

Does the drone act as a TCP client or server. Or is the traffic UDP?

How does the drone acquire it's IP address?

qyiet

454 posts

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#1365591 13-Aug-2015 14:28

wasabi2k:
If you are clever about it you could try and change the location 2 subnet to include all the devices already in it (i.e. if they are all from .1-.50), then it wouldn't be too much of a major, they would pick up a new subnet mask when they renew.

Great minds think alike.. I was just checking that, but location2 seems to have IPs scattered widely the DHCP pool would be easy to deal with, but there are static IPs at both ends of the 254 addresses they have, and I'll be betting software that references it. :(.

I think I may have a workaround though.. testing it.

Warning: reality may differ from above post

qyiet

454 posts

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#1365597 13-Aug-2015 14:30

roobarb: Does the drone act as a TCP client or server. Or is the traffic UDP?

How does the drone acquire it's IP address?

The drone acts as a server, and it's IP address is set statically. I don't know if it sends traffic via UDP or TCP I've not looked that closely, however I'd assume there at least some UDP in there for video transmission.

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qyiet

454 posts

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#1365666 13-Aug-2015 16:07

qyiet: I think I may have a workaround though.. testing it.

Really what I did was this:

wasabi2k: ...you could try and change the location 2 subnet to include all the devices already in ...

I'm sure I'm going to catch hell for moving some of the stuff around, but 90% of it was able to be put in the 192.168.1.253/25 subnet via DHCP, so I've done that and reconfigured the last 10%. Leaving the 192.168.1.127/25 subnet free for the drone. (not sure if I'm writing these subnets correctly)

I still seem to have communication to the location2 lan, and I've preconfigured the dronelan at location1, I just need to get the wifi online and test the drone.

Warning: reality may differ from above post