Ethernet Switches & Routers

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sfportero
Posts: 1
Registered: ‎01-10-2013

Cannot ping server - ARP Issue

Hi,

I got problem where I cannot ping server from a Cisco switch connected to the FastIron SX 800. It occur in random time..

I have checked the server connection to SX but there is no problem, the server can ping other server and switches in the network.

I attached the detail of topology:

ARP-FastIron800.jpg

SW1 and 2: CISCO WS-C2970G-24TS-E
CORE 1 and 2: Brocade FastIron SX 800, v. 07.3.00bT3e3.

Server: Solaris 10.

I cant ping from switch 2 to server:

SW2#ping 10.43.1.211

Type escape sequence to abort.

Sending 5, 100-byte
ICMP Echos to 10.43.1.211, timeout is 2 seconds:

  .....

Success rate is 0 percent (0/5)

However I can ping from SW1 to server:

SW1#ping 10.43.1.211

Type escape sequence to abort.

Sending 5, 100-byte
ICMP Echos to 10.43.1.211, timeout is 2 seconds:

!!!!!

Success rate is 100
percent (5/5), round-trip min/avg/max = 1/202/1006 ms

The SW2's MAC is not present in the server ARP table.

Server sniffer:

  1. 10.43.1.211 -> (broadcast)  ARP C Who is 10.43.1.35, 10.43.1.35 ?

SW2 sniffer:

Jan  9 09:21:29: IP ARP: rcvd req src 10.43.1.211 0021.281a.6950, dst 10.43.1.35 Vlan100

Jan  9 09:21:29: IP ARP: sent rep src 10.43.1.35 0011.bb91.c141, dst 10.43.1.211 0021.281a.6950 Vlan100

The ARP response never reaches the server.

If I do an clear apr-cache in SW2, then it send a gratiutous ARP message to all network and the ping works.

SW2# clear arp-cache

Jan  9 17:44:20: IP ARP: sent rep src 10.43.1.35 0011.bb91.c141, dst 10.43.1.35 ffff.ffff.ffff Vlan100

Jan  9 17:44:20: IP ARP: rcvd rep src 10.43.1.211 0021.281a.6950, dst 10.43.1.35 Vlan100

Jan  9 17:44:22: IP ARP: creating incomplete entry for IP address: 10.43.1.211 interface Vlan100

Jan  9 17:44:22: IP ARP: sent req src 10.43.1.35 0011.bb91.c141, dst 10.43.1.211 0000.0000.0000 Vlan100

Jan  9 17:44:22: IP ARP: rcvd rep src 10.43.1.211 0021.281a.6950, dst 10.43.1.35 Vlan100

Server sniffer:

10.43.1.35 -> *            ARP C Who is 10.43.1.211, 10.43.1.211 ?

10.43.1.211 -> 10.43.1.35   ARP R 10.43.1.211, 10.43.1.211 is 0:21:28:1a:69:50

10.43.1.35 -> 10.43.1.35   ARP R 10.43.1.35, 10.43.1.35 is 0:11:bb:91:c1:41

Now, the ARP response reaches the server and ping works until the MAC-IP entry expires in server ARP table.

Another workaround:

Adding static entry in server ARP table.

     arp -s 10.43.1.35 00:11:bb:91:c1:41 temp

Its like the DEFECT000357433 bug but its was closed in version 07.3.00:

Defect ID: DEFECT000357433

Technical Severity: High

Summary: Layer 3 traffic sometimes does not get forwarded on an FCX stack.

Symptom: IP Traffic is not forwarded on an FCX stack’s member units.

Workaround: Clearing the MAC or ARP tables temporarily resolves the problem.

Probability: Low

Feature: FCX Layer 3 Forwarding - IPV4

Function: Data Forwarding (IPV4)

Reported In Release: FI 07.2.02

Service Request ID: 601967

Any ideas?

Thanks.

Occasional Contributor
dbowen
Posts: 5
Registered: ‎04-25-2011

Re: Cannot ping server - ARP Issue

I am seeing a similar issue on code 7.3e on FCXs.  Has any progress been made on this?

Frequent Contributor
dvenkat
Posts: 118
Registered: ‎06-15-2009

Re: Cannot ping server - ARP Issue

sfportero,


The reason could be anything why it’s not working.  It would be best to have a TAC case open so that they can review the configuration, code release, and then try to replicate the issue.  Once replicated, they can isolate the cause and come up with a solution.  It could even be an issue with the cat switches. 

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