Odd issue, unable to connect locally (destination unreachable)

snowdog · 15 Feb 2016 at 10:42

Hello,

I have this odd issue where a pc shares its connection with a device fine, but is unable to ping this device:

-Device 2 can access the internet (as can pc1 obviously)
-PC1 has no firewall
-PC1 does not know the MAC address of Device 2 in its ARP table until device 2 actively connects to the internet, after this the MAC address appears in the ARP table, but windows is still unable to ping device 2.
-Device 2 responds to pings OK normally (tested on other network).

What could this be, what kind of stupid situation is this that Windows is smart enough to route internet traffic to device 2, but is unable to ping the device :confused:

.
The same setup works on other exact same hardware configs. Pinging 192.168.253.200 from pc1 gives either a timeout or ''destination host unreachable''.

Steveocee · 15 Feb 2016 at 13:18

I don't understand what you are trying to achieve or what is going on?

Why is the AP and device 2 on a separate subnet?

why is the router not where the internet connection is?

BigT · 15 Feb 2016 at 13:29

I don't know the ins and outs of internet connection sharing in Windows, but if it's like the routes on my cascading routers in my home network then given the IP addresses and subnets you've provided I would expect device 2 to be able to ping anything in the 192.168.254.x space on the network PC1 is on but not the other way around. ICS is doing NAT I think so unless the request originates from device 2 you can't connect from PC1, including pinging it.

I think, but someone with better networking knowledge will know better than me, that if your subnet mask on both networks is 255.255.0.0 instead of 255.255.255.0 then it may all just work as both networks will share the 192.168.x.x space.

snowdog · 15 Feb 2016 at 13:45

Steveocee said:
I don't understand what you are trying to achieve or what is going on?

Why is the AP and device 2 on a separate subnet?

why is the router not where the internet connection is?

Router is a 4g modem.

AP is a wifi card in the pc. Device 2 is a pin terminal (verifone vx680) . Situation: in car pin device that is being driven by software on the pc.

The problem this is a new pc, 10+ pc's with the exact same configuration (or from what I can see) work fine.

snowdog · 15 Feb 2016 at 18:34

Appears to have been pebkac :rolleyes:

in combination with the pin terminal going into some kind of sleep mode for wifi.

Application of the customer which uses our software (to handle payments) had a bug with a payment stuck (which was caused by him not installing a required service in the first place), and the guy didn't correctly ensure it was a network or software issue (he didn't see ping work once, so after that continued testing with just the complete software package not paying attention to network troubleshooting).

Always nice wasting time on an issue that appears to not be an issue in hindsight. I shouldn't agree to phone troubleshooting without Teamviewer or Logmein.

bledd · 16 Feb 2016 at 07:31

ICS should never have been invented. Use a router, or a switch if there's a router already.

snowdog · 17 Feb 2016 at 13:05

bledd. said:
ICS should never have been invented. Use a router, or a switch if there's a router already.

A hardware change would be hard to do for the customer, we are not the party who does the networking, we just provided extra help as a service to keep good relations as we are the party who built a bit of the software.

This is how it has been implemented, and this will have to do, they have over 800 cars in their fleet outfitted with the hardware... Do you imagine the costs of outfitting a whole fleet with new hardware? I personally agree that a decent solution would be a simple switch and AP in the 192.168.254.x network.

What is wrong with ICS btw? It's often a much cheaper solution, we have used ICS in one of our recent projects too and it works fine, it allows sharing an internet connection with a 2nd device (like a pin terminal) without the costs of expensive extra hardware and space. All you need is a cheap Embedded single board computer with dual Lan, no big clunky routers that take up space, power supply troubles (a single small cheap 12v psu is enough for pc and pin and whatever peripherals or other embedded boards), etc... In this case there is space, but in many small embedded solutions there is no space for a router.

When we first got ADSL in 2001 or 2002, I also had internet through ICS in Win xp, because a pci lan card was much cheaper than an expensive switch or hub. Besides, cheap routers are often a bigger headache than ICS. I never had problems with overloading Windows with a huge ammount of connections, while Sweex, Linksys (WRT54G), and various Cisco routers (EPC3925 and EPC-3928, the most used consumer Cable routers here) often **** themselves with more than 50 simultaneous connections and need a (hard) reset.

bledd · 17 Feb 2016 at 15:47

VX680 menu screen = :/