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I have a server running WHS 2011, a desktop PC running Win 10 Pro 64 bit and a laptop running Win 10 Home 64 bit. The desktop PC is often used to connect to my office network using Cisco AnyConnect. Last week I suddenly stopped being able to connect to my server when AnyConnect was running. Investigation showed that it was no longer able to talk to it using IPv4. The laptop will still ping the server using the v4 address and the desktop will talk to other network devices using the v4 address, but for some reason not the server.
I've tried a lot of searches but the main answer seems to be to turn off IPv6. When I try this on either the server or the desktop PC I can no longer communicate with the server at all, whether AnyConnect is running or not.
I've tried removing the IPv6 binding from the AnyConnect virtual adapter but this doesn't help either.
The server has a static IP address with a number of ports forwarded to it (it handles email and www services). DHCP is being handled by the PlusNet router.
Any suggestions please?
John
Additional: as requested, here's the output from ipconfig/all
Windows IP Configuration
Host Name . . . . . . . . . . . . : Osprey-SSD
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : myworkplace.net
myworkplace.net
myworkplace.net
lan
Ethernet adapter Ethernet 2:
Connection-specific DNS Suffix . : myworkplace.net
Description . . . . . . . . . . . : Cisco AnyConnect Secure Mobility Client Virtual Miniport Adapter for Windows x64
Physical Address. . . . . . . . . : 00-05-9A-3C-7A-00
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::18dc:ce67:8f38:aefa%3(Preferred)
Link-local IPv6 Address . . . . . : fe80::2ae6:54bd:4280:26c6%3(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.254.84(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : ::
DHCPv6 IAID . . . . . . . . . . . : 50333082
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1F-D8-5F-66-EC-08-6B-02-04-57
DNS Servers . . . . . . . . . . . : 172.30.10.20
172.30.10.23
Primary WINS Server . . . . . . . : 172.30.10.20
NetBIOS over Tcpip. . . . . . . . : Enabled
Ethernet adapter Ethernet:
Connection-specific DNS Suffix . : lan
Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
Physical Address. . . . . . . . . : EC-08-6B-02-04-57
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::79d3:f0f:9b6f:bd8b%13(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.1.102(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : 02 March 2017 06:20:37
Lease Expires . . . . . . . . . . : 03 March 2017 06:20:40
Default Gateway . . . . . . . . . : 192.168.1.254
DHCP Server . . . . . . . . . . . : 192.168.1.254
DHCPv6 IAID . . . . . . . . . . . : 65800299
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-1F-D8-5F-66-EC-08-6B-02-04-57
DNS Servers . . . . . . . . . . . : 192.168.1.254
NetBIOS over Tcpip. . . . . . . . : Enabled
Tunnel adapter isatap.lan:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : lan
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
Tunnel adapter isatap.myworkplace.net:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . : myworkplace.net
Description . . . . . . . . . . . : Microsoft ISATAP Adapter #2
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
TVJohn
Posted 2017-03-01T11:43:27.027
Reputation: 11
1Hold on, just because IPv4 stopped working doesn't automatically mean it "only uses IPv6"... (Not to mention your ipconfig dump doesn't even show an IPv6 address for your computer.) – user1686 – 2017-03-02T09:03:11.280
So what is the Link-local IPv6 Address? If I do tracert by the server name this is what I get: Tracing route to Peregrine [fe80::a136:892b:53e7:413d%13] over a maximum of 30 hops:
Using the IP address I get this:
I can post the IPConfig output before I connect to the work network if that would help. – TVJohn – 2017-03-02T13:20:34.273
Looks like your Cisco VPN is giving you a bogus IPv6 gateway address. It's time to have a chat with your company's IT department. I don't think the Internet can help you with this. – Michael Hampton – 2017-03-02T20:57:05.827
Already done that, and they swear nothing has changed. Everything was working fine a week ago. Why am I unable to talk to my server using its IPv4 address? – TVJohn – 2017-03-03T08:23:26.417
I've noticed that the device 'Microsoft Kernel Debug Network Adapter' has appeared under network adapters. This is certainly not something I've enabled myself. Could this be related? – TVJohn – 2017-03-08T08:53:44.577