I am seeing a strange problem with my WS2008R2 server I believe is related to networking. The symptom is that 6% of all attempts to ping the server using tcp fails. For example, from another machine, I see:
$ nc -vz 172.25.79.12 11555
Connection to 172.25.79.12 11555 port [tcp/*] succeeded!
$ nc -vz 172.25.79.12 11555
Connection to 172.25.79.12 11555 port [tcp/*] succeeded!
$ nc -vz 172.25.79.12 11555
nc: connect to 172.25.79.12 port 11555 (tcp) failed: Connection timed out
$ nc -vz 172.25.79.12 11555
Connection to 172.25.79.12 11555 port [tcp/*] succeeded!
I see this regardless of port, and this problem was first reported as 6% of the users' attempts to connect to the SQL Server database timing out.
We started seeing this around the time we connected an external storage device from pogo linux to the server using iSCSI. Indeed, when we disconnect the device, the symptom disappears. The reason it was attached directly to the server was because it is being used by SQL Server to store an archive database, and we wanted the best performance possible. (We are a very resource limited department.)
I don't have network experience, and was wondering if there are any smoking guns in my routing table and config. Any tips or advice would be very much appreciated.
Microsoft Windows [Version 6.1.7601] Copyright (c) 2009 Microsoft Corporation. All rights reserved. C:\>route print =========================================================================== Interface List 16...00 21 9b 92 6b 91 ......Broadcom BCM5709C NetXtreme II GigE (NDIS VBD Clie nt) #7 15...00 21 9b 92 6b 93 ......Broadcom BCM5709C NetXtreme II GigE (NDIS VBD Clie nt) #6 1...........................Software Loopback Interface 1 =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 172.25.79.100 172.25.79.12 266 1.2.3.0 255.255.255.0 On-link 1.2.3.1 266 1.2.3.1 255.255.255.255 On-link 1.2.3.1 266 1.2.3.255 255.255.255.255 On-link 1.2.3.1 266 127.0.0.0 255.0.0.0 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 127.0.0.1 306 172.25.79.0 255.255.255.0 On-link 172.25.79.12 266 172.25.79.12 255.255.255.255 On-link 172.25.79.12 266 172.25.79.255 255.255.255.255 On-link 172.25.79.12 266 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 1.2.3.1 266 224.0.0.0 240.0.0.0 On-link 172.25.79.12 266 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 1.2.3.1 266 255.255.255.255 255.255.255.255 On-link 172.25.79.12 266 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 0.0.0.0 0.0.0.0 172.25.79.100 Default 0.0.0.0 0.0.0.0 172.25.100.100 Default =========================================================================== IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 1 306 ::1/128 On-link 1 306 ff00::/8 On-link =========================================================================== Persistent Routes: None
C:\>ipconfig /all Windows IP Configuration Host Name . . . . . . . . . . . . : embarrassing.hostname.redacted Primary Dns Suffix . . . . . . . : department.domain1.redacted Node Type . . . . . . . . . . . . : Hybrid IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : department.domain1.redacted department.domain2.redacted Ethernet adapter Local Area Connection 3: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom BCM5709C NetXtreme II GigE (NDIS VBD Client) #7 Physical Address. . . . . . . . . : 00-21-9B-92-6B-91 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 1.2.3.1(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : NetBIOS over Tcpip. . . . . . . . : Enabled Ethernet adapter Local Area Connection 2: Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Broadcom BCM5709C NetXtreme II GigE (NDIS VBD Client) #6 Physical Address. . . . . . . . . : 00-21-9B-92-6B-93 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes IPv4 Address. . . . . . . . . . . : 172.25.79.12(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Default Gateway . . . . . . . . . : 172.25.79.100 DNS Servers . . . . . . . . . . . : 128.95.112.1 128.95.120.1 NetBIOS over Tcpip. . . . . . . . : Enabled