Unable to ping until arp cache cleared - Page 4

samirshaikh52 · ‎02-04-2014

Hello Experts

I have 3 servers connected to Cisco Catalyst Switch C2960 and this switch has uplink to one of the access switch and ultimately this access switch connected to our 2 Core Switch

We are running HSRP and core switches has direct link between them.

Today I encountered an issue these server are unreachable from vlans other that its own. I just cleared arp-cache and it started pinging.

Please can you help since this happening repeadetly.

Thanks

samirshaikh52 · ‎02-04-2014

Thos are Linux Servers

May be I need to clear arp cache on servers ??

Jon Marshall · ‎02-04-2014

Maybe but i would wait until you have talked to the server guys.

If you need a temporary fix just use the one you have been using.

Jon

samirshaikh52 · ‎02-04-2014

Waiting server's team reply.

For temp I kept continous ping to the VIP 10.1.1.17 and its working.

samirshaikh52 · ‎02-05-2014

They have 2 servers running linux OS. They have checked the servers but no issues found.

Once the problem occurs I cannot ping all the below IP's

But the problem is with only Server 2

Server 1 is working fine.

Here is the interface details

bond0 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.15 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

RX packets:916867429 errors:0 dropped:0 overruns:0 frame:0

TX packets:765935729 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:900507151734 (858790.5 Mb) TX bytes:538632706090 (513680.1 Mb)

bond0:0 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.21 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

bond0:2 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.23 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

bond0:3 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.17 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

samirshaikh52 · ‎02-05-2014

This is weird issue making us mad. Please I request for help.

Thanks

JohnTylerPearce · ‎02-05-2014

The switch that these two servers are teamed to, what is the model number and specific IOS version?

samirshaikh52 · ‎02-05-2014

WS-C2960G-24TC-L

Catalyst 2960G IOS 12.2(25)SEE

Jon Marshall · ‎02-05-2014

We really need to know how the Linux setup is meant to work. This is not (according to your description) a single server that is teamed, this is two servers running some sort of HA software that presents them as one VIP so packets going to that VIP are spread among the two physical servers.

It's very difficult to help without more details. If we knew what the software was we could perhaps do some reading on how it is meant to work.

All the other servers in that vlan are working so it points to some interaction between the HA setup and the switches.

Once the problem occurs I cannot ping all the below IP's

But the problem is with only Server 2

Server 1 is working fine.

what exactly is the problem ? Is it that end clients cannot connect to the VIP address ie. i assume end clients do not connect to the real IPs.

Jon

samirshaikh52 · ‎02-05-2014

I have 2 servers. Server 1 has IP 10.1.1.14, 10.1.1.18.There is no issues with this server

Now coming back to server 2

This is the configuration of interfaces on linux server 2 .Once the issue occurs I cannot ping any the below IP's

bond0 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.15 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

RX packets:916867429 errors:0 dropped:0 overruns:0 frame:0

TX packets:765935729 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:900507151734 (858790.5 Mb) TX bytes:538632706090 (513680.1 Mb)

bond0:0 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.21 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

bond0:2 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.23 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

bond0:3 Link encap:Ethernet HWaddr 00:14:5E:BC:74:66

inet addr:10.1.1.17 Bcast:10.1.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1

samirshaikh52 · ‎02-05-2014

Two server have HA.

Server 2 is active. The clients are pointing 10.1.1.17 to connect to this server. This server has a problem Lets forget about HA and server 1.

samirshaikh52 · ‎02-05-2014

The server team says 10.1.1.17 works as VIP

samirshaikh52 · ‎02-05-2014

I have noted one more thing while doing continous ping to 10.1.1.17 the reply is 1ms but at some intervals it gives 10ms then again to 1ms

samirshaikh52 · ‎02-05-2014

I have a thought maybe nic on server 2 causing the issue ?

samirshaikh52 · ‎02-05-2014

Please let me know your question that will help us to identify the problem I will forward to the server team.

Aabed Khalifa · ‎02-06-2014

Can you print out arp results at both servers at the problem time and at the normal operation time ? Also can you you print our arp for the 3 IP's ( 2 physica and 1 VIP ) at the problem time and at normal operation ?

I know this is somehow out of context but this looks like an IP conflict for me .

Also print out logs from Cores at the problem time .