First of all, try to understand (draw) your connection. What's your WAN interface, what's your LAN interface (fe in my case is LAN: eth0, WAN: eth1). This way you know where you're looking. A picture is saying a lot more then some words.
I'll put some basic test here that can point you to the right place where to look...
ConnectCan you connect with ssh to your core? I'll assume you're using a linux client.
ssh username@192.168.80.1
Network interfacesWith ifconfig, you'll see a lot more about your network cards.
ifconfig
-> do you see any errors on the interfaces (collisions)? In fact, you should only see RX/TX packets here...
-> What the subnetmask of you interfaces (the same as for your routing table)?
fe
eth0 Link encap:Ethernet HWaddr 00:21:85:5d:d6:05
inet addr:192.168.80.1 Bcast:192.168.80.255 Mask:255.255.255.0
inet6 addr: fe80::221:85ff:fe5d:d605/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:4338750 errors:0 dropped:0 overruns:0 frame:0
TX packets:2156345 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1817464938 (1.8 GB) TX bytes:161459655 (161.4 MB)
Interrupt:219 Base address:0xa000
eth1 Link encap:Ethernet HWaddr 00:04:76:97:7b:98
inet addr:192.168.0.184 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::204:76ff:fe97:7b98/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:49496 errors:0 dropped:0 overruns:0 frame:0
TX packets:32634 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:26781428 (26.7 MB) TX bytes:7483598 (7.4 MB)
Interrupt:21 Base address:0xac00
For more information, you can always do following:
sudo ethtool -S eth0
This should give you more information:
NIC statistics:
tx_packets: 2190314
rx_packets: 4367767
tx_errors: 0
rx_errors: 0
rx_missed: 0
align_errors: 1166
tx_single_collisions: 0
tx_multi_collisions: 0
unicast: 4350464
broadcast: 11762
multicast: 5541
tx_aborted: 0
tx_underrun: 0
Routingnetstat -rn
-> should give you a clear routing table
fe
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 <<<Your WAN network>>>
192.168.80.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 <<<Your LAN network>>>
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth1 <<<All the rest to your internetprovider>>>
TracerouteWith a traceroute you'll see the connection path. This is useful to see where your connections goes, and if any devices are taking a long time to respond.
This is best done from you client machine on (i don't have direct access to a client now, so i can't show you my result, sorry).
traceroute linuxmce.org
fe (this is done from another network, so it won't be the same for you). The most important thing in here are the first lines, with your private ip's, and the first public ip (your internetrouter):
traceroute to linuxmce.org (193.200.113.133), 30 hops max, 60 byte packets
1 192.168.80.1 (192.168.80.1) 3.575 ms 3.778 ms 4.355 ms <<< Your internal gateway >>>
2 192.168.0.1 (172.31.31.1) 7.338 ms 7.716 ms 7.932 ms <<< Your internet gateway >>>
3 3.123-123-109.adsl-dyn.isp.belgacom.be (109.123.123.3) 14.416 ms 16.522 ms 19.280 ms <<< Your public ip >>>
4 160.241-183-91.adsl-static.isp.belgacom.be (91.183.241.160) 21.939 ms 24.110 ms 26.778 ms
5 ae-15-1000.ibrstr1.isp.belgacom.be (91.183.246.107) 52.974 ms 31.339 ms 53.332 ms
6 bru-11-r6-t9-4.car.belbone.be (80.84.20.18) 36.676 ms bru-11-r6-t8-4.car.belbone.be (80.84.20.78) 13.732 ms bru-11-r6-t7-4.car.belbone.be (80.84.21.34) 14.288 ms
7 94.102.162.50 (94.102.162.50) 17.156 ms 19.748 ms 22.358 ms
8 neotelecoms.bnix.net (194.53.172.79) 31.315 ms 33.714 ms 36.135 ms
9 xe0-0-0.tcr1.gs.par.as8218.eu (83.167.55.20) 58.078 ms 58.461 ms 58.842 ms
10 83.167.56.155 (83.167.56.155) 62.023 ms 64.715 ms 67.321 ms
11 xe0-1-1.r06.uni.vie.at.nextlayer.net (212.69.191.150) 67.712 ms 69.814 ms 35.678 ms
12 xe4-1-1.r05.rdh.vie.at.nextlayer.net (92.60.3.144) 38.981 ms xe2-1-0.r05.rdh.vie.at.nextlayer.net (92.60.2.144) 39.179 ms xe4-1-1.r05.rdh.vie.at.nextlayer.net (92.60.3.144) 40.699 ms
13 vl21.r02.rdh.vie.at.nextlayer.net (81.16.147.192) 43.634 ms 45.582 ms 50.315 ms
14 abaton.rdh.vie.at.nextlayer.net (81.16.148.34) 51.541 ms 37.767 ms 39.880 ms
15 193.200.112.37 (193.200.112.37) 41.829 ms 43.772 ms 45.978 ms
16 94.247.144.120 (94.247.144.120) 48.424 ms 50.878 ms 53.792 ms
17 193.200.113.133 (193.200.113.133) 55.457 ms 35.938 ms 38.298 ms
Send us the results of this, from there on we can maybe start troubleshoot a bit more ...
Of course, it's best that you do all this tests from all the machines (or at least all the machines that are in the loop). This is the reason why i wrote that's always best to have a small drawing beside... This way, you can isolate the problem to a certain point/connection...