I have a very strange problem. I have 2 Cisco 6500 switches with hsrp . I have created VLAN 400 with no svi . In this switches i also have 2 trunk ports that im connecting a vmware server that has a team interface this 2 trunk ports and a virtual switch. Behing this virtual switch it is a virtual machine in VLAN 400 with ip 10.100.140.1
In cisco 6500 i have connect another cisco router into an access port in vlan 400 and i have him an ip 10.100.140.100 . My problem is that Virtual machine can ping and communicate with this router but if no traffic pass for a few minutes , the router lose connectivity with the virtual machine. If i initiate a ping from the VM to the router then connectivity is restored. In router if i give a show arp i also see that i cannot found the mac of the VM . It appears again when i initiate ping from vm to router.
Any ideas ?
Thanks a lot
I think default value for arp cache timeout is 4 hours on Cisco routers. Can you check what the arp cache timeout value is on this router?
There is a work around of creating a static arp on the router for the vm so it will never timeout.
Hello and thanks for the answer ,
I thing that the arp cache timeout is the default which is 240 minutes . But the problem appears after 10-15 minutes without any traffic passing . Then i send a ping and connectivity is restored.
I have thought also this workaround but im searching first for a solution or any ideas .
Can you check what the arp timeout value is on the router's interface that's connected to 6500? Router shouldn't flush a dynamic arp entry before the arp cache time out value unless IOS is corrupted.
sh int f0/0
FastEthernet0/0 is up, line protocol is up
Hardware is DEC21140, address is ca07.4378.0000 (bia ca07.4378.0000)
Internet address is 192.168.1.7/24
MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:02, output 00:00:09, output hang never
Last clearing of "show interface" counters never
Arp timeout is set to 4 hours . I manage to solve the issue by using a new VLAN with a subnet with SVI. Previous VLAN has no SVI . Now all seems to work without any problems. Off course it is still a mystery this behavior
I agree with Hitesh that there seems to be an issue on the VM, but that shouldn't affect the arp table on router. That still remains a mystery.