I have a really strange Windows 7 IPv4 routing issue that I can't get to the bottom of. The summary of the issue is that the default gateway is set to 192.168.254.253, but that it is actually using a default gateway of 192.168.254.254. Here's a network diagram: .-,( ),-. .-( )-. .-----( internet )----.--------------------------. | '-( ).-' | | | '-.( ).-' | | v v v .------------. .------. .------. | 10mb Fibre | | ADSL | | ADSL | '------------' '------' '------' | | | | | | v v v .---------------------. .--------------------. .--------------------. | Juniper Box | | Draytek DSL Router | | Draytek DSL Router | |---------------------| |--------------------| |--------------------| | (public IP address) | | 172.16.0.x | | 172.16.0.x | '---------------------' '--------------------' '--------------------' | | | | | .-------------------' | v v v .-------------------------. .-----------------. | Draytek Dual WAN Router | | Untangle GW | |-------------------------| |-----------------| | 192.168.254.254 | | 192.168.254.253 | '-------------------------' '-----------------' | | | | | v v =================================== LAN =================================== | | | | v v .----------------. .----------------. | Windows 7 W/S | | Windows 7 W/S | |----------------| |----------------| | 192.168.254.38 | | 192.168.254.77 | '----------------' '----------------' This is a recently (a few weeks ago) converted fibre site with the original 2 DSL lines still attached and running. An Untangle (firewall) was installed with the fibre line. Here is the affected PC network configuration: C:\>ipconfig /allcompartments /all Windows IP Configuration ============================================================================== Network Information for Compartment 1 (ACTIVE) ============================================================================== Host Name . . . . . . . . . . . . : COMP36 Primary Dns Suffix . . . . . . . : XXXXXX.local Node Type . . . . . . . . . . . . : Broadcast IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : XXXXXX.local Ethernet adapter Local Area Connection 2: Connection-specific DNS Suffix . : XXXXXX.local Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller #2 Physical Address. . . . . . . . . : C8-9C-DC-33-F1-65 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::3925:86a5:7066:ab92%15(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.254.38(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : 22 August 2012 10:20:32 Lease Expires . . . . . . . . . . : 30 August 2012 10:20:31 Default Gateway . . . . . . . . . : 192.168.254.253 DHCP Server . . . . . . . . . . . : 192.168.254.200 DHCPv6 IAID . . . . . . . . . . . : 315137244 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-14-4A-17-8D-10-78-D2-74-2F-8A DNS Servers . . . . . . . . . . . : 192.168.254.200 Primary WINS Server . . . . . . . : 192.168.254.200 NetBIOS over Tcpip. . . . . . . . : Enabled Tunnel adapter isatap.XXXXXX.local: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : XXXXXX.local Description . . . . . . . . . . . : Microsoft ISATAP Adapter Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Tunnel adapter Teredo Tunneling Pseudo-Interface: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes The routing table: C:\>route print =========================================================================== Interface List 15...c8 9c dc 33 f1 65 ......Realtek PCIe GBE Family Controller #2 1...........................Software Loopback Interface 1 10...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter 11...00 00 00 00 00 00 00 e0 Teredo Tunneling Pseudo-Interface =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.254.253 192.168.254.38 10 127.0.0.0 255.0.0.0 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 127.0.0.1 306 192.168.254.0 255.255.255.0 On-link 192.168.254.38 266 192.168.254.38 255.255.255.255 On-link 192.168.254.38 266 192.168.254.255 255.255.255.255 On-link 192.168.254.38 266 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 192.168.254.38 266 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 192.168.254.38 266 =========================================================================== Persistent Routes: None IPv6 Route Table =========================================================================== Active Routes: If Metric Network Destination Gateway 1 306 ::1/128 On-link 15 266 fe80::/64 On-link 15 266 fe80::3925:86a5:7066:ab92/128 On-link 1 306 ff00 ::/8 On-link 15 266 ff00::/8 On-link =========================================================================== Persistent Routes: None And the strange routing as demonstrated by tracert: C:\>tracert -d www.bbc.co.uk Tracing route to www.bbc.net.uk [212.58.246.95] over a maximum of 30 hops: 1 1 ms 1 ms <1 ms 192.168.254.254 2 1 ms 1 ms 1 ms 172.16.0.254 3 17 ms 18 ms 16 ms XXXXXXXXXXXXXXX 4 18 ms 19 ms 19 ms XXXXXXXXXXXXXXX 5 22 ms 22 ms 22 ms XXXXXXXXXXXXXXX 6 22 ms 21 ms 22 ms XXXXXXXXXXXXXXX 7 21 ms 21 ms 22 ms 217.41.169.109 8 30 ms 32 ms 57 ms 109.159.251.227 9 46 ms 39 ms 35 ms 109.159.251.137 10 27 ms 66 ms 30 ms 109.159.254.116 ^C However, when done from another Windows 7 workstation: C:\Users\administrator>ipconfig /allcompartments /all Windows IP Configuration ============================================================================== Network Information for Compartment 1 (ACTIVE) ============================================================================== Host Name . . . . . . . . . . . . : PABX-BACKUP Primary Dns Suffix . . . . . . . : XXXXXX.local Node Type . . . . . . . . . . . . : Broadcast IP Routing Enabled. . . . . . . . : No WINS Proxy Enabled. . . . . . . . : No DNS Suffix Search List. . . . . . : XXXXXX.local Ethernet adapter Local Area Connection: Connection-specific DNS Suffix . : XXXXXX.local Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller Physical Address. . . . . . . . . : 8C-89-A5-94-43-84 DHCP Enabled. . . . . . . . . . . : Yes Autoconfiguration Enabled . . . . : Yes Link-local IPv6 Address . . . . . : fe80::9479:1c11:6f9f:ae0b%11(Preferred) IPv4 Address. . . . . . . . . . . : 192.168.254.77(Preferred) Subnet Mask . . . . . . . . . . . : 255.255.255.0 Lease Obtained. . . . . . . . . . : 15 August 2012 08:27:18 Lease Expires . . . . . . . . . . : 27 August 2012 08:27:31 Default Gateway . . . . . . . . . : 192.168.254.253 DHCP Server . . . . . . . . . . . : 192.168.254.200 DHCPv6 IAID . . . . . . . . . . . : 244091301 DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-16-C2-79-BE-8C-89-A5-94-43-84 DNS Servers . . . . . . . . . . . : 192.168.254.200 Primary WINS Server . . . . . . . : 192.168.254.200 NetBIOS over Tcpip. . . . . . . . : Enabled Tunnel adapter isatap.XXXXXX.local: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : XXXXXX.local Description . . . . . . . . . . . : Microsoft ISATAP Adapter Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Tunnel adapter Local Area Connection* 9: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Microsoft 6to4 Adapter Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes Tunnel adapter Teredo Tunneling Pseudo-Interface: Media State . . . . . . . . . . . : Media disconnected Connection-specific DNS Suffix . : Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0 DHCP Enabled. . . . . . . . . . . : No Autoconfiguration Enabled . . . . : Yes C:\Users\administrator> And finally, doing a tracert from the 2nd workstation yields expected results: C:\Users\administrator>tracert -d www.bbc.co.uk Tracing route to www.bbc.net.uk [212.58.244.67] over a maximum of 30 hops: 1 <1 ms <1 ms <1 ms 192.168.254.253 2 1 ms 1 ms 1 ms 141.0.xxx.xxx 3 2 ms 2 ms 2 ms 141.0.xxx.xxx 4 7 ms 2 ms 2 ms 109.204.xxx.xxx 5 2 ms 2 ms 2 ms 95.177.0.7 6 3 ms 2 ms 2 ms 95.177.0.9 7 30 ms 2 ms 2 ms 95.177.0.2 8 2 ms 2 ms 2 ms 195.66.224.103 9 ^C As expected, it is routing via .253, and the 2nd hop is the inside interface of the Juniper NTU. I've not inspected the traffic yet. In particular, I was going to look for ICMP redirects, though why there would be an ICMP redirect at all is not really sensible? .254 used to be the default gateway before the fibre was installed. Any ideas? Doesn't make sense to me why there should be this routing issue :( The Draytek Dual WAN Router was rebooted, the PC was rebooted. The PC had the network disabled and then re-enabled. All the standard stuff when Windows looses the plot. Hopefully somebody recognises the symptoms! PS: Sorry for the long post, but I didn't want to leave something potentially relevant out. PPS: No iSCSI involved on/at this or any other workstation so Windows 7 routing traffic through the gateway for local addresses isn't the issue.