Invalid IP - RBR20

[rbussolotti]

Hi,

I was assigned a public IP address from my ISP and when configuring it to my router I keep receiving the Invalid IP message.

I checked it and I accurately made all the settings as indicated by my ISP. The IP class is xxx.yyy.zzz.kkk/31

My ISP says that the issue is on the router since they think it doesn't support the RFC 3021.

Can it be that a new router like the RBR20 with the latest firmware installed (V2.6.2.104) doesn't support the class /31 and RFC 3021?

Thank you

r

[CrimpOn]

What subnet mask has been entered for this static IP address? (255.255.255.254)?

Typically the gateway address is in the same subnet as the static IP address.

A /31 IP address allows for only two hosts in the subnet. (device and gateway)..It had never occured to me to wonder how ISP's would assign static IP's.  This implies that for every static IP they assign, they burn another IP address from their pool for the gateway.

Learn something every day.

[rbussolotti]

Hi,
Thanks for answering.
Yes the settings are as follows:

IP: xxx.yyy.zzz.67
Subnet Mask: 255.255.255.254 (as foreseen in the point/point connections following RFC 3021 specificatiins - https://tools.ietf.org/html/rfc3021)
Gateway: xxx.yyy.zzz.66
DNS Primario: 8.8.8.8
DNS Secondario: 1.1.1.1

Any suggestion?
Thank you

[CrimpOn]

I am guessing that this Orbi is past the 90 days of "complimentary support"?

It's ironic that the upper levels of ISP tech support almost certainly have direct links to the major modem and router manufacturers.

Surely Netgear supports an RFC from 20 years ago.

Reading the RFC, my first impression was that the IP's are "backward", i.e. the local host should be 66 and the network end 67.

But, that defies common sense.  They provide static IP's all the time.

When does the "Invalid IP" error message come up?  Does it provide any information besides "Invalid"?

[rbussolotti]

Hi,

you're more than right on the 90 days.

No other indication given. The precise message is "192.168.1.1 says Invalid IP" and I get it when I click "Save" after inserting all the parameters.

Thank you

[CrimpOn]

Did you try clicking "Test" before clicking "Apply"?

[rbussolotti]

Yes. Same.

[CrimpOn]

I found a fascinating discussion of RFC3021 where the poster recommended using /30 rather than /31 claiming "it will still work".

Does the ISP have a "Level 2" support tier?

(with my (former) Time Warner (now) Spectrum, I had to escalate to Level 2 over several issues.)

[rbussolotti]

Yes,

the ISP said that if the router doesn't support the RFC 3021 they can provide a /30 class IP at an additional monthly fee. eheheh.

[CrimpOn]

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@rbussolotti wrote:

the ISP said that if the router doesn't support the RFC 3021 they can provide a /30 class IP at an additional monthly fee. eheheh.

---

What a deal (not). Actually, I believe the advice was to cheat. Put in the static IP and the gateway IP and then use a /30 subnet mask instead of a /31 mask. Any broadcasts generated by the router would just 'disappear' 

Several internet searches have turned up similar questions for other Netgear routers, but no definite answers.

Does this ISP have a list of supported routers?

[rbussolotti]

Hi,

I played with the subnet mask a bit.

So:

The invalid IP message was indeed because of the subnet mask .254

I then tried to put .252 but I got the message "Invalid Subnet mask" (???).

The only way fwd was to put .248 and everything went fine. Still unclear to me how come a good device like the Orbi RBR20 has these kind of issues while when putting all the parameters with /31 subnet in my 20 euro wifi router everything worked smoothly at first attempt...

BTW thanks a million for the support.

r

[CrimpOn]

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@rbussolotti wrote:

The invalid IP message was indeed because of the subnet mask .254

I then tried to put .252 but I got the message "Invalid Subnet mask" (???).

The only way fwd was to put .248 and everything went fine.

---

Truly disappointing.  Since subnet masks must be "all 1's starting on the left and then all zeros", the only valid subnet masks are 128. 192, 224, 240, 248, 252, and 254. which correspond to /24, /25, /26, /27, /28, /29, /30, /31

II wonder how common it is to use a pair of IP's to define Static IP's?  A Class C address, for example, would support about 252 customers (reserving 0, 255 for broadcast, one for the gateway) but only 126 customers using two IP's for each.

The "point to point" method may be more secure.  Even if one customer cheats and uses a wider subnet mask, none of the other customers will respond to him because they are limited to the single connection.

p.s. I have sent private messages to two forum moderators asking for comment and not heard back from either.

[Blanca_O]

Hi @rbussolotti

Welcome to NETGEAR Community!

This is interesting. Please allow me to check this with the team and we'll get back to you. 

Regards,
Blanca
Community Team

[rbussolotti]

Hi Bianca,

I was wondering if you heard any news from the team.

Thanks a million

r

[rbussolotti]

@Bianca have you heard anything from the team. This issue is anything quite odd.
Thanks