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Re: new 5406zl switches - heavy packet loss

 
Paulen
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Hi,

The one thing that springs to my mind is IP issues - doublecheck that subnet masks are identical, no double interfaces with double default gws on the server etc. Do you do routing or just L2 connection?

/BT
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Hi Paulen

The ip addresses the switches have is the same as the old switches. Also, we're not using L3 functionality at all (no routing). Only L2 being used.

As for "double default gws on the server", it happens to many servers (mixed physical & VMware) etc.

Thanks for your input.

Luq
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Typical symptom when pinging a server from my PC. Both devices on the same 5406zl switch.


C:\>ping -t 172.18.16.77

Pinging 172.18.16.77 with 32 bytes of data:

Reply from 172.18.16.77: bytes=32 time<1ms TTL=128
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Matt Hobbs
Honored Contributor

Re: new 5406zl switches - heavy packet loss

Can you attach the output of 'ipconfig /all' from both the server and problem client - and also capture the output of 'arp -a'.
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

C:\>ping -t 172.18.16.77

Pinging 172.18.16.77 with 32 bytes of data:

Reply from 172.18.16.77: bytes=32 time<1ms TTL=128
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 172.18.16.77:
Packets: Sent = 11, Received = 1, Lost = 10 (90% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Control-C
^C

CLIENT:
C:\>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : luqman
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Description . . . . . . . . . . . : Broadcom 440x 10/100 Integrated Controller
Physical Address. . . . . . . . . : 00-15-60-C7-B1-9A
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 172.18.17.68
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . : 172.18.16.1
DHCP Server . . . . . . . . . . . : 172.18.16.65
DNS Servers . . . . . . . . . . . : 172.18.16.65
172.18.16.67
Primary WINS Server . . . . . . . : 172.18.16.65
Secondary WINS Server . . . . . . : 172.18.18.67
Lease Obtained. . . . . . . . . . : 30 April 2007 08:26:53
Lease Expires . . . . . . . . . . : 07 May 2007 08:26:53

C:\>

SERVER:
C:\>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : carna
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Broadcom NetXtreme Gigabit Ethernet
Physical Address. . . . . . . . . : 00-15-60-4F-76-2E
DHCP Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 172.18.16.77
Subnet Mask . . . . . . . . . . . : 255.255.254.0
Default Gateway . . . . . . . . . : 172.18.16.1
DNS Servers . . . . . . . . . . . : 172.18.16.65

C:\>
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

CLIENT:
C:\>arp -a

Interface: 172.18.17.68 --- 0x2
Internet Address Physical Address Type
172.18.16.1 00-09-43-e9-a8-c0 dynamic
172.18.16.65 00-50-56-88-44-10 dynamic
172.18.16.67 00-50-56-88-23-73 dynamic
172.18.16.77 00-e0-b6-06-ef-6a dynamic
172.18.16.79 00-c0-b6-07-c6-69 dynamic
172.18.16.91 00-0e-7f-21-0e-6d dynamic
172.18.16.120 00-11-43-cd-27-d4 dynamic

C:\>

Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Hi Matt

One more thing; the problem only occurs on the local LAN or so it seems. If I ping the same ip address from a routed network (eg. our DMZ), the ping always gets a response (no nat).

However, having said that, on the same internal LAN, while I get a response from one PC, I don't get a response from another.

Luq
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Matt

Something else very interesting.... when I clear the arp cache on the server side, it starts to work, but not for long:

SERVER:
C:\>ping -t 172.18.17.68 (my PC/client)

Pinging 172.18.17.68 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.

Ping statistics for 172.18.17.68:
Packets: Sent = 3, Received = 0, Lost = 3 (100% loss),
Control-C
^C
C:\>arp -d *

C:\>ping -t 172.18.17.68

Pinging 172.18.17.68 with 32 bytes of data:

Reply from 172.18.17.68: bytes=32 time<1ms TTL=128
Reply from 172.18.17.68: bytes=32 time<1ms TTL=128
Reply from 172.18.17.68: bytes=32 time<1ms TTL=128
Reply from 172.18.17.68: bytes=32 time<1ms TTL=128

Ping statistics for 172.18.17.68:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 0ms, Maximum = 0ms, Average = 0ms
Control-C
^C
C:\>
Matt Hobbs
Honored Contributor

Re: new 5406zl switches - heavy packet loss

It seems like there is an IP address conflict between the server and another device:

Physical Address. . . . . . . . . : 00-15-60-4F-76-2E
DHCP Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : 172.18.16.77
Subnet Mask . . . . . . . . . . . : 255.255.254.0

172.18.16.77 00-e0-b6-06-ef-6a dynamic

You need to track down 00-e0-b6-06-ef-6a and fix the conflict.
Luqman Achmat
Regular Advisor

Re: new 5406zl switches - heavy packet loss

Thanks Matt

I just noticed that myself. Will track it down and hopefully resolve the connectivity issues to the other servers too.

Luq