Problem with LAN's, routing, ARP, or something else

Ritter Rs · ‎06-18-2016

Perhaps this discussion is not in right topic, but it contain some Cisco equipment and I am trying to understand problem.
so my apologies if I am on wrong place, but I know that are people with the best networking knowledge are here.

Short:
My ISP GW device (no option to add routes) - 192.168.0.0/24 - My router 192.168.1.1/24 - My cisco Switch (contain VLANs) - 192.168.2.0/24, 192.168.3.0/24, 192.168.4.0/24

Question:
I have Internet access from PC3 (192.168.2.0/24).
But I am not able to ping PC1 or PC2 (192.168.0.0/24).
I have to ping 192.168.0.1 (ISP GW device) then I am able to ping 192.168.0.10 and 192.168.0.150, but after a few minutes I am not able to ping PC1 and PC2 till I manually ping 192.168.0.1.
What is problem? Why I shoud first ping 192.168.0.1?
I didn't notice any change in arp tables.

I know that I should put PC1 and PC2 in some VLAN other then 192.168.0.0/24, but I am trying to figure out where is problem in this scenario.

Thanks for any help.

Detail:
My ISP GW Cisco EPC3925,
TP-LINK openwrt as router,
Cisco Catalyst contains some VLANs.

----ISP Cisco EPC3925 Voice GW - address 192.168.0.1
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|
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TP-LINK OPENWRT
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port WAN 192.168.0.3/24
port LAN 192.168.1.1/24
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Cisco 3560
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VLAN 10 192.168.0.2
VLAN 11 192.168.1.2
VLAN 20 192.168.2.0/24 (vlan interface 192.168.2.1)
VLAN 30 192.168.3.0/24 (vlan interface 192.168.3.1)
VLAN 40 192.168.4.0/24 (vlan interface 192.168.4.1)
|
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Gi0/10 PC1 192.168.0.10/24 VLAN 10
Gi0/11 PC2 192.168.0.150/24 VLAN 10
Gi0/12 PC3 192.168.2.20/24 VLAN20

Routing tabele:
1) ISP Cisco EPC3925 There is no option to manually add a route, so I have to use TP-Link as a router

2) TP-LINK openwrt

root@OpenWrt:~# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.0.1 0.0.0.0 UG 0 0 0 eth0.2
192.168.0.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0.2
192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 br-lan
192.168.2.0 192.168.1.1 255.255.255.0 UG 1 0 0 br-lan
192.168.3.0 192.168.1.1 255.255.255.0 UG 1 0 0 br-lan
192.168.4.0 192.168.1.1 255.255.255.0 UG 1 0 0 br-lan

3) Cisco 3560

Switch#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is 192.168.1.1 to network 0.0.0.0

C 192.168.0.0/24 is directly connected, Vlan10
C 192.168.1.0/24 is directly connected, Vlan11
C 192.168.2.0/24 is directly connected, Vlan20
S* 0.0.0.0/0 [1/0] via 192.168.1.1

4) PC3 192.168.2.20
IPv4 Route Table
===========================================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 192.168.2.1 192.168.2.20 281
127.0.0.0 255.0.0.0 On-link 127.0.0.1 306
127.0.0.1 255.255.255.255 On-link 127.0.0.1 306
127.255.255.255 255.255.255.255 On-link 127.0.0.1 306
192.168.2.0 255.255.255.0 On-link 192.168.2.20 281
192.168.2.20 255.255.255.255 On-link 192.168.2.20 281
192.168.2.255 255.255.255.255 On-link 192.168.2.20 281
224.0.0.0 240.0.0.0 On-link 127.0.0.1 306
224.0.0.0 240.0.0.0 On-link 192.168.2.20 281
255.255.255.255 255.255.255.255 On-link 127.0.0.1 306
255.255.255.255 255.255.255.255 On-link 192.168.2.20 281
===========================================================================
Persistent Routes:
Network Address Netmask Gateway Address Metric
0.0.0.0 0.0.0.0 192.168.2.1 Default

johnd2310 · ‎06-18-2016

HI,

Why do you have vlan 10 as 192.168.0.0/24 and you isp link as 192.168.0.0/24.? Can't you change vlan 10 network address?

Routes on OpenWrt are not correct as well. Routes for 12.168.2.0/24 , 192.168.3.0/24 and 192.168.4.0/24 should point to 192.168.1.2(cisco 3560) and not 192.168.1.1(OpenWRT)

To further troubleshoot, you will have to go to PC2 and PC1 and have a look at their arp and routing table. what can you\can't you ping from PC1 and PC2?

Thanks

John

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Ritter Rs · ‎06-18-2016

Thank you John.

I've got from my ISP Cisco EPC3925 Voice GW and there is no option to add static routes to my VLANs, so I put router (openwrt) between GW and Catalyst 3560, because of routing.

Yes I can change VLAN10 network address, but 192.168.0.0/24 is inside address from GW.

Maybe this is better for understanding this situation:

Cisco GW

Public IP (200.50.50.33) ------- Cisco GW -------Private IP (192.168.0.1)

TP-LINK (openwrt)

TO Cisco GW (192.168.0.3) ------OpenWRT------TO LAN (192.168.1.1)

Catalyst 3560

switchport access VLAN 10, to Cisco GW LAN

switchport access VLAN10, to OpenWRT WAN

switchport access VLAN11, to OpenWRT LAN

I made changes to OpenWRT, so now is 192.169.1.2 gw for VLANs on Catalyst SW.

I am not sure, why I can ping PC1 (192.168.0.10) only if I first make ping to 192.168.0.1?

Ritter.