IPv6: You cannot enter a network IP for Gateway IP

Hello Khuram!

As mentioned by H_Patel, you can't use the Network IP for IP address. However you can use 511. 

Also in the XG you would need to enter it this way.

Copy and paste from here and you should be ok.

2401:0:4000::511

2401:0:4000::513

Regards,

Hello Khuram!

As mentioned by H_Patel, you can't use the Network IP for IP address. However you can use 511. 

Also in the XG you would need to enter it this way.

Copy and paste from here and you should be ok.

2401:0:4000::511

2401:0:4000::513

Regards,

not possible as 513 is another host in network

gateway must be 510 as others are working with this config screen is below

Hi,

510 is the broadcast address for the network range you have been allocated.

ian

agreed, ISP says it should work fine everywhere, dont know what they have configured. and it is working fine everywhere other than sophos 

Technically you have two addresses available and they are 511 and 512, 510 is a broadcast address and would not normally be used a gateway. This not just a sophos issue, it is a general networking design and it is not as if they are short of address space.  They appear to work like it is IP4 addressing and in short supply. All my networks using IP4 were done with a /30 network which is equivalent to your /126. My networks were all using Cisco routers.

In theory this is basic networking 101. More updates.
ian

tried, doesn't work as 513 is a usable client IP not gateway's IP, see my Ubuntu screen below am using 513 IP there with gateway 510 working fine.

What you are actually saying is that your /126 in not really a true /126 on your ISP's network. You still didn't answer the question about the network range you are assigned for use on your internal network. There is no use having a IPv6 external interface address without being able to use an internal address. 

Ian

Is it possible to set the gateway IP using a link local address?

Yes, my isp does and the Mac mini does and so does the iPad.

ian