Technical Discussion
  >> Home Networking, Internet Connection Sharing, etc.


Register (or login) on our website and you will not see this ad.


Pages in this thread: 1 | 2 | 3 | 4 | (show all)   Print Thread
Standard User Woolwich
(experienced) Fri 11-Mar-22 09:04:48
Print Post

Why does DHCP pool start at 38 not 1


[link to this post]
 
Playing with a new router which does DHCP. In default setup its DHCP pool is from 192.168.1.38 to 192.168.1.243.

Why?!

Is there an RFC or some other rules suggesting where a pool starts and stops? Why not start at 1 and go to 254?

If its to 'protect' fixed addresses for routers or other devices, how come the suggested default client IP pool for VPN users runs from 240 to 249? Or is this just a misconfiguration on my part? Should I drop the DHCP pool back down to 239? Or increase it to 249?
Standard User Pheasant
(knowledge is power) Fri 11-Mar-22 09:13:00
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
Nope this seems a bit arbitrary. What box is it?
Standard User jchamier
(eat-sleep-adslguide) Fri 11-Mar-22 09:14:22
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
In reply to a post by Woolwich:
Why?!
The decision of the network designer. Some like to leave .1 to .20 for networking devices in a subnet, others like to leave .240 to .254. On enterprise networks I've seen the default gateway as .1 or .254 and in at least one case the network designer chose .100. I have no idea what they were thinking smile

22 years of broadband connectivity since 1999 trial - Live BQM


Register (or login) on our website and you will not see this ad.

Standard User Pheasant
(knowledge is power) Fri 11-Mar-22 09:15:19
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
Btw typically the gateway is .1 so the pool would start from .2 on most setups.
Standard User Woolwich
(experienced) Fri 11-Mar-22 09:15:22
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Pheasant] [link to this post]
 
In reply to a post by Pheasant:
What box is it?


EdgeRouter X. But I'm pretty sure I've noticed this on other routers like FritzBox and maybe DrayTek.
Standard User Pheasant
(knowledge is power) Fri 11-Mar-22 09:34:08
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
As said, a predilection of the designer. Personally would’ve set it to 42 - the answer to the life, the universe, and everything (of course) 🤣

There’s nothing written in any RFCs about starting or stopping a DHCP scope at a particular address. You can edit the scope as you see fit.
Standard User Woolwich
(experienced) Fri 11-Mar-22 09:42:02
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Pheasant] [link to this post]
 
OK understood now. Unusually its simpler than expected!

Any comments about my VPN pool though? The default 38 to 243 is in the routers GUI but I've added

Text
1
23
4
client-ip-pool {
             start 192.168.1.240             stop 192.168.1.249
         }

in the CLI. Am I actually only going to be able to issue four addresses (240 to 243) to VPN clients?
Standard User Pheasant
(knowledge is power) Fri 11-Mar-22 09:49:36
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
Keep the pools no overlapping.

Otherwise set/adjust the size, depending on how many max simultaneous clients you need to accommodate.
Standard User Woolwich
(experienced) Fri 11-Mar-22 09:54:30
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Pheasant] [link to this post]
 
In reply to a post by Pheasant:
Keep the pools no overlapping.

Otherwise set/adjust the size, depending on how many max simultaneous clients you need to accommodate.


Thanks. So this is really two different pools? Even though I can only see one of them via the GUI. Anyway, I will research more. Thanks again.
Standard User neilll
(regular) Fri 11-Mar-22 11:03:29
Print Post

Re: Why does DHCP pool start at 38 not 1


[re: Woolwich] [link to this post]
 
It's normal in Business to use separate DHCP pools for Clients and VPN users, just a bit weird to see it on a home device.

Also as someone else said, reserving the first 10-20 addresses for a Default Gateway and static stuff like switches is also good for OCD smile

Regards,
Neill

ZeN Fibre Active (FTTC 46.68/7.94)
Check Point SG730/Vigor 130
Exchange - Corby (EMCRRBY)
Pages in this thread: 1 | 2 | 3 | 4 | (show all)   Print Thread

Jump to