DHCP addresses not unique

[Pottsy]

Not an expert here, but...

Getting problems where devices connected to the 7800DXL are reporting IP address conflicts. They are using DHCP assigned ip addresses.

Sure enough, looking at the DHCP table, it is handing out the same address twice. Am I doing something wrong? In this example, it has allocated .1.76 twice.

[billion_fan]

Have you setup a static IP lease for the two devices in question??

What DHCP range is set??

[Pottsy]

My static IP lease list is empty!

The range is from .72 to .99

[billion_fan]

My static IP lease list is empty!

The range is from .72 to .99

This is a strange one, normally the router will assign IP's one by one, so I am not sure why two devices with different MAC addresses will get the same IP address from the DHCP server.

Try setting up the S9 with a static IP lease, copy and paste the mac address from the DHCP table and enter it in the 'Static IP Lease List' with a IP address outside the DHCP range, once done, restart the S9, and see if the issue occurs again.

[afeakes]

I had the same problem a while back. Turns out for me it was that I had setup interface groups to try and separate guest access from family access. gave up in the end so have no groups and never had a duplicate IP address since.

not sure if you have setup any interface groups but this was my problem. See "Interface grouping" on page 76 of the manual.

thanks

[billion_fan]

I had the same problem a while back. Turns out for me it was that I had setup interface groups to try and separate guest access from family access. gave up in the end so have no groups and never had a duplicate IP address since.

not sure if you have setup any interface groups but this was my problem. See "Interface grouping" on page 76 of the manual.

thanks

Also check the guest network, and make sure the DHCP range does not include 192.168.2.1 eg try the range of 192.168.2.100 ~192.168.2.199

[billion_fan]

I had the same problem a while back. Turns out for me it was that I had setup interface groups to try and separate guest access from family access. gave up in the end so have no groups and never had a duplicate IP address since.

not sure if you have setup any interface groups but this was my problem. See "Interface grouping" on page 76 of the manual.

thanks

Also check the system log within the router, once the IP conflict has occurred and let me know what is logged there

[Pottsy]

I had the same problem a while back. Turns out for me it was that I had setup interface groups to try and separate guest access from family access. gave up in the end so have no groups and never had a duplicate IP address since.

not sure if you have setup any interface groups but this was my problem. See "Interface grouping" on page 76 of the manual.

thanks

Also check the guest network, and make sure the DHCP range does not include 192.168.2.1 eg try the range of 192.168.2.100 ~192.168.2.199

Aha - I did have 192.168.2.1 in the guest network range, so have changed it as you suggest. Will monitor...

Log includes entries like this:

Code: Select all

Jan 14 18:57:28 daemon err syslog: dhcpd:sending ACK to 192.168.1.77
Jan 14 19:14:54 daemon err syslog: dhcpd:192.168.1.72 belongs to someone, reserving it for 3600 seconds
Jan 14 19:14:56 daemon err syslog: dhcpd:sending OFFER of 192.168.1.73
Jan 14 19:14:56 daemon err syslog: dhcpd:sending ACK to 192.168.1.73
Jan 14 19:20:31 daemon err syslog: dhcpd:192.168.1.74 belongs to someone, reserving it for 3600 seconds
Jan 14 19:20:33 daemon err syslog: dhcpd:sending OFFER of 192.168.1.75

[billion_fan]

I had the same problem a while back. Turns out for me it was that I had setup interface groups to try and separate guest access from family access. gave up in the end so have no groups and never had a duplicate IP address since.

not sure if you have setup any interface groups but this was my problem. See "Interface grouping" on page 76 of the manual.

thanks

Also check the guest network, and make sure the DHCP range does not include 192.168.2.1 eg try the range of 192.168.2.100 ~192.168.2.199

Aha - I did have 192.168.2.1 in the guest network range, so have changed it as you suggest. Will monitor...

Log includes entries like this:

Code: Select all

Jan 14 18:57:28 daemon err syslog: dhcpd:sending ACK to 192.168.1.77
Jan 14 19:14:54 daemon err syslog: dhcpd:192.168.1.72 belongs to someone, reserving it for 3600 seconds
Jan 14 19:14:56 daemon err syslog: dhcpd:sending OFFER of 192.168.1.73
Jan 14 19:14:56 daemon err syslog: dhcpd:sending ACK to 192.168.1.73
Jan 14 19:20:31 daemon err syslog: dhcpd:192.168.1.74 belongs to someone, reserving it for 3600 seconds
Jan 14 19:20:33 daemon err syslog: dhcpd:sending OFFER of 192.168.1.75

From looking at the system log, the router knows the ip ending with 74 is assigned to another device and is offering 75 to the device instead

[Pottsy]

Update...

I could solve my problems by removing the guest network, but I really wanted this so went about it another way.

DHCP on the main (default) network continued to not work, with many address conflicts (some devices reporting a conflict and requesting another address, other devices just locking). The solution was to find another DHCP server on the network (a Synology NAS works well) and just pass through any requests on that network to the Syno box. I still use the 7800 for DHCP on the guest network. Oddly though, DHCP has now disappeared from the Status pages, so I can't see the client table for the guest network.

DHCP is a bit broken on the 7800 (all my entries were subject to the 2 hours 43 minute thing), and it would be nice to see it fixed. Using the Synology box, requests are dealt with instantly, so all the waiting for a connection and random disconnects and conflicts are a thing of the past.