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Router changes static IP addresses by itself

cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Router changes static IP addresses by itself

Technicolor TG582n
I have 6 different machines that I have set up with consecutive static IP addresses and I want them to stay that way
192.168.101
192.168.102
192.168.103
192.168.104
192.168.105
192.168.106
But the router decides that it wants to mess with me and change 1 or 2 of them to something it decides, then I fix them again and then everything repeats to infinity.
DHCP is not an option as the router gives out arbitrary addresses and I can't find a way to make it give out consecutive starting from a certain number.
Any ideas?
10 REPLIES 10
Superuser
Superuser
Posts: 7,254
Thanks: 1,157
Fixes: 76
Registered: ‎30-07-2007

Re: Router changes static IP addresses by itself

If you're OK with using telnet to access the router then you can get it to fix DHCP leases by Mac address. See here http://npr.me.uk/telnet.html , the section titled 'change Lan IP of a connected device'
cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself


Thank you. I hope they stay this way and do not change to some other IPs:
Everything looks OK?

Adie:quote
cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself

Guys, I need your help with the weirdest problem:
Since yesterday 6 of my machines have started to disappear from my local network all of a sudden and that happens too often now.
All my miners are connected to a TP-Link TL-SF1008D 8-Port 10/100Mbps Unmanaged Desktop Switch, which is then connected to the router Technicolor TG582n:

When the problems happens the blinking light at the back of the router, where the switch is connected has gone off, yet the all 7 lights (6 miners + incoming cable) are ON on the switch.
Until yesterday I wasn't sure what is the problem, but now I know: when I unplug the switch from the router and plug it back in = they re-appear back in the network.
Additionally this morning my own PC reported network conflict: some other machine on the network got its IP too, which never happened.
+ I have setup the DHCP table manually. The 101 to 106 are the machines in question. Before it said state USED and now it is free, but they are visible.

Do you have any experience with bad switches? Any ideas what is causing the issue?
Thank you.
cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself

I have just applied DHCP settings at each machine and all of a suddent FREE changed to USED in the DHCP server list. That was probably the whole problem, but any idea why it happens?
Btw the machines are Beaglebone Blacks, so its Linux with a web interface where I can change Network settings:
Community Veteran
Posts: 6,773
Thanks: 258
Fixes: 21
Registered: ‎16-02-2009

Re: Router changes static IP addresses by itself

I had a similar problem with the 582. It would change addresses marked as static. One of the many reasons I got rid of it.
How old is your router & switch?
I have had a switch die on me before (the Gib ports decided they weren't) and the connection led's were off.
Highlighted
cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself

Well mine doesn't change them or at least the only change I can see see is USED turning to FREE in the DHCP server table.
But when I open the router web page the IP addresses (101 to 106) are all there with machines marked as Inactive.
The router is from June this year when I switched to Plusnet.
The switch is 2 weeks old.
At least now I know what the problem is and will monitor it.
I wish there was an explanation of this behaviour.
adie:quote
Superuser
Superuser
Posts: 7,254
Thanks: 1,157
Fixes: 76
Registered: ‎30-07-2007

Re: Router changes static IP addresses by itself

Quote
But when I open the router web page the IP addresses (101 to 106) are all there with machines marked as Inactive.
That's what you would expect if they've lost their DHCP lease.
Have you tried connecting the switch to a different port on the router, just to eliminate the port as the problem ?
Rippong
Grafter
Posts: 41
Thanks: 1
Registered: ‎23-12-2013

Re: Router changes static IP addresses by itself

You can use static IPs on the PC itself without needing to configure the router.
Leave the router doing it's DHCP thing (for example 192.168.1.100 - 192.168.1.200 for devices that need it
Set the Static IPs on the computers/devices between 192.168.1.201 - 192.168.1.230
Set the subnet mask, gateway and DNS manually (255.255.255.0, gateway with TGN is 192.168.1.254 and I use google DNS 8.8.8.8 and 8.8.4.4
You don't have to configure the router, unless it's port forwarding and it's nice and easy.

cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself

Quote from: MisterW
Quote
But when I open the router web page the IP addresses (101 to 106) are all there with machines marked as Inactive.
That's what you would expect if they've lost their DHCP lease.
Have you tried connecting the switch to a different port on the router, just to eliminate the port as the problem ?

Last time it happened I switched from the last port to the 3rd one, but I also re-applied the DHCP settings at the machines, so not sure what helped. I think it was the latter.
Quote from: Rippong
You can use static IPs on the PC itself without needing to configure the router.
Leave the router doing it's DHCP thing (for example 192.168.1.100 - 192.168.1.200 for devices that need it
Set the Static IPs on the computers/devices between 192.168.1.201 - 192.168.1.230
Set the subnet mask, gateway and DNS manually (255.255.255.0, gateway with TGN is 192.168.1.254 and I use google DNS 8.8.8.8 and 8.8.4.4
You don't have to configure the router, unless it's port forwarding and it's nice and easy.


Very good idea. I just checked and the router DHCP pool is from .64 to .253, so I will use Static IP addresses below .64:

Btw the machines are reporting this:
root@Jupiter-2:~# ps | grep dhcp
  324 root      2148 S    udhcpc -b -x hostname Jupiter-2 eth0
  965 root      2148 S    udhcpc -b -x hostname Jupiter-2 eth0
3679 root      2152 S    grep dhcp
I am not a Linux guru, so no idea if there are supposed to be 3 lines. Anyone?
cyper
Dabbler
Posts: 20
Registered: ‎18-07-2013

Re: Router changes static IP addresses by itself

The saga continues:
6 machines are set with static IP addresses. Today one of them decided to change its IP address from 192.168.1.6 (static) to 192.168.1.73 (DHCP)
These are the settings from the machine:

These are the settings in the router and if I select "Always use the same IP address" it switched to 192.168.1.73 automatically.

This is the results from dhcp server lease list via Telnet:

The other 5 machines are set up in the same manner and they are shown as having static IP addresses in the router. The IP range given to the machines is outside the DHCP range.
So why does this happen?
Also last night all 6 machines decided to disappear from the network. They were set using DHCP by manually adding them to the DHCP table via Telnet. After this incident I set static addresses for them and still issues.