devices on the LAN can't ping me

cris9288 · 2013-08-11 15:48:14

I'm trying to get around an issue that has been troubling me ever since I moved from charter to centurylink (moved across state) : it seems that my devices can not see each other on the LAN.

Here are my devices:

roku in the living room.
my laptop (arch)
2nd laptop (windows 8)
android phone (4.2.2)
ipod touch
pc (windows 7)

I first noticed the problem when I tried to set up Plex on my laptop. My roku would always fail to find the server on start up, but after a few pings from my laptop to the roku it became visible. This would reset everyday.

I also have a remote app on my phone to control my roku over the network. I would run into the same problem here, where my phone couldn't see my roku at first, but after a few pings and a little time it would recognize the device on the network.

Also, I could not ping any devices from my laptop. I got around this by adding static host names to /etc/hosts - now my laptop can find the other devices. However, one more issue remains: It looks like none of the other devices can see my laptop, with the exception of the roku. A ping from my phone and my 2nd laptop both return destination not found.

The real issue here is that nobody can ping my laptop. My phone has trouble pinging my windows laptop, but that doesn't really matter to me since I don't any apps on there that need to communicate over the LAN.

I would appreciate and advice and any help you guys can come up with. Thank you.

Last edited by cris9288 (2013-08-11 16:06:06)

cris9288 · 2013-08-11 16:58:55

anyone? It's a very strange issue...sometimes a device will be able to ping another, and sometimes it can't. Lately though, no device has been unable to reach my laptop. I can't ssh to it, my roku doesn't detect its Plex server, and I can't ping to it from my phone either. Now suddenly, I can ping it from my windows laptop when I wasn't able to before.

Whatever the source of the problem is, it's annoying the hell out of me because it's not consistent and I don't know where to attack it from. Could it be an issue with my router? I'm hoping someone might have an idea.

t0m5k1 · 2013-08-11 18:22:04

are all the devices in the LAN on the same subnet as the router?
what are the default routes for each device & does each device use the same default gateway?

if no then that could be the problem!

if the answer is yes then:

does each device use a static ip or dhcp?
if dhcp then check the service is running & giving out leases to all device's if that does not fix it then temporarily disable it on the router & try each device with a static IP & check again, if working the check dhcp log file & config for issue's
if static then do any devices use the same IP as another device (ip conflict)?
if yes change the duplicate to unused IP.

Last edited by t0m5k1 (2013-08-11 18:33:29)

cris9288 · 2013-08-11 19:15:59

are all the devices in the LAN on the same subnet as the router?

yes all devices are on the same LAN and have the same subnet mask/

what are the default routes for each device & does each device use the same default gateway?

the default routes for each device is the same: 192.168.0.1 and this is also the default gateway for each device.

there aren't any duplicate IP's and I know that dhcp is running on all my devices. I'll try and fiddle around with dhcp and see if there is anything interesting there. Thanks for your reply.

Everything seems to be working fine now, strangely enough. The only thing I did was to change a suspicious looking setting in my router's DNS configuration page. It lets me use a default setting or specify custom servers. I set my router as the primary DNS server, while the secondary server was prefilled with my ISP's provided DNS server. Hopefully that was the source of my problem, but it's hard to say because my router actually doesn't show me what the default DNS ip's were.

Last edited by cris9288 (2013-08-11 19:19:13)

t0m5k1 · 2013-08-12 18:10:44

Glad you got it sorted.

These kind of issue's can be so hard to troubleshoot but I find it best to deal with the basic connectivity first.

please mark as [SOLVED]

Last edited by t0m5k1 (2013-08-12 18:12:09)

cris9288 · 2013-08-12 23:08:44

well it's not really solved. It seems like my devices will randomly decide to forget each other or suddenly clear their routing tables and become not able to reach each other over the LAN. The thing is, it's my understanding that if there is no route to a particular destination and if the destination still matches the subnet of the default gateway the source will just forward a packet there. In that case, my router should have a route to all the devices on the LAN or else wouldn't be able to access the internet right?

So If I say "ping some.host" and the source device cannot find it in it's routing tables, it will, by default (assuming a normal home LAN configuration) send the packet to the router. The router will then have to figure out where to forward packets to. Is this correct?

Arch Linux

#1 2013-08-11 15:48:14

devices on the LAN can't ping me

#2 2013-08-11 16:58:55

Re: devices on the LAN can't ping me

#3 2013-08-11 18:22:04

Re: devices on the LAN can't ping me

#4 2013-08-11 19:15:59

Re: devices on the LAN can't ping me

#5 2013-08-12 18:10:44

Re: devices on the LAN can't ping me

#6 2013-08-12 23:08:44

Re: devices on the LAN can't ping me

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