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Setting DHCP at home router. But It gets full?

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deep1234    1

Hi guys. I have the Tp-Link Archer C7. Since I have about 12 devices connects to the internet. I set the DHCP to 192.168.1.50 to 192.168.1.200. That's about 150 IP's. 

Amazingly, it gets full. I checked the web access and some have reached 192.168.1.198!!! 

 

Some of the who uses the internet. Tells me that they cant connect for some time. I am suspecting that they are no more IP's to the router can give and they can connect only after the lease time finishes (I have 120 min which is the default).

 

Please advice me.  

 

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dead.cell    4,037
18 minutes ago, deep1234 said:

Hi guys. I have the Tp-Link Archer C7. Since I have about 12 devices connects to the internet. I set the DHCP to 192.168.1.50 to 192.168.1.200. That's about 150 IP's. 

Amazingly, it gets full. I checked the web access and some have reached 192.168.1.198!!! 

 

Some of the who uses the internet. Tells me that they cant connect for some time. I am suspecting that they are no more IP's to the router can give and they can connect only after the lease time finishes (I have 120 min which is the default).

 

Please advice me.  

 

  • Is this for home or business?
  • Are you checking the clients connecting via DHCP on your router? 
  • Are these client devices connected yours?  If not, who's are they? (customers, guests, etc)
  • Do you have an open WiFi network that's allowing anyone within the vicinity to connect?

I'd be hard pressed for you to run out of IP addresses if you're connecting only ~12 devices.  

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Skiver    1,947

Does your router actually list which devices have which IPs, can you be sure that the leases aren't expiring? Could it not simply be that as a device requests an IP and then releases it, it simply works through the list rather than re-allocating no longer used IPs?

 

 

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+BudMan    3,401
1 hour ago, deep1234 said:

I am suspecting that they are no more IP's

Well this should be easy enough to check.. Even if the dhcp server is utter crap.  What does ipconfig /all of a windows machine connected show for its dhcp lease time?

 

example

IPv4 Address. . . . . . . . . . . : 10.56.153.176(Preferred)
  Subnet Mask . . . . . . . . . . . : 255.255.255.0
  Lease Obtained. . . . . . . . . . : Thursday, February 15, 2018 9:20:42 AM
  Lease Expires . . . . . . . . . . : Friday, February 16, 2018 3:35:42 AM

 

When you do a /release and /renew do you get a new IP, your old one - does it not grab an ip?  If something is odd I would sniff the traffic on this machine and see if the dhcpd answer back with a NAK, some other IP that the client is turning down, etc..

 

Do your clients enter and leave the network all the time... Or do they connect and stay connected all day?  Client with a 2 hour lease should get a renewal of that IP every hour..  And not use up another lease... If your dhcp server is not doing renewals, and the client runs out of the 2 hour lease and then does a discover and gets another IP then sure even 12 clients could eat through your available IP space..

 

But your dhcpd should drop the lease after the 2 hours expires and it was not renewed.  Take it your using the default firmware on this C7 router?  I would look to put say dd-wrt or openwrt or some other 3rd party firmware that would be able to give you some better insight into the dhcp leases used and available, etc.

 

But depending on the dhcpd - it could hand out from the top down, or the bottom up.. It could reuse old leases that have expired as soon as available and stay on one side of your pool or the other or it could work its way through the pool and not reuse an OLD lease until its walked all the way through the pool address space.

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