SOLVED! Cannot See Comcast Wireless, But Others are Good

[Vorlon]

Summary Issue: Comcast XFinity Router (802.11n) is invisible when using my monolithic kernel, but visible when using Gentoo Live CD. Other routers are visible and wireless works well on other routers.

I've built a few dozen Gentoo systems over the past decade, all with monolithic kernels. I'm currently using a relatively young Dell latitude with Intel wireless hardware (iwlwifi driver). I can see and connect to my home router, and several other routers, but my girlfriend's comcast router does not even appear on my iwlist. However, when I boot to the Gentoo Live CD, it sees this router without any trouble. Obviously, something about my particular setup is preventing me from seeing this particular router.

Here's more data:
- lspci shows: "Network controller: Intel Corporation Wireless 7265 (rev 59)"
- iwlwifi driver
- iwlwifi-7265D-29.ucode firmware
- Stable AMD64 system
- No error messages in dmesg
- Comcast router is 802.11g/n
- Home router is 802.11g
- Minstrel 802.11n support enabled in the kernel
- Cannot connect even when I explicitly put in the SSID & password. (In other words, the router is not just just "hidden", but not seen at all)

Here's what I've checked so far, looking for differences between my setup and the Gentoo Live CD
- Same driver used (Intel iwlwifi)
- Both loaded as modules
- Same firmware in both
- same version of iwlwifi kernel module in both
- Verified the same kernel selections are made in both my kernel and the Live CD
- Logged into router and changed mode to 802.11b/g/n (Can't disable "n" mode)

I suspect the problem is that my kernel will not see an 802.11n router for some reason.

Does anybody have any suggestions for other things to check?

TIA!
_________________
Casey Bralla
Chief Nerd in Residence
The NerdWorld Organisation

[NeddySeagoon]

Vorlon,

I suspect the problem in that your Comcast router is using old broken discredited tkip and your Gentoo is not.

The real solution is to not use tkip in the router as its insecure. Configure it for WPA2 only.
That will break other wireless devices that do not have WPA2 support, if any.

The fallback is to use tkip in Gentoo. Its still there but off by default.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

[Vorlon]

Wow. That was the problem. I shut off tkip by accessing the router's control panel and changed the "security mode" from the default of "WPAWPA2-PSK (TKIP/AES) (recommended)" to "WPA2-PSK (AES)". That solved the problem. Thank you NeddySeagoon

(You won't believe how long I've struggled with this. <sigh>)
_________________
Casey Bralla
Chief Nerd in Residence
The NerdWorld Organisation

[Vorlon]

Update: It turns out that I had not set the tkip use variable (I didn't even know it existed).

The problem wasn't a buggy tkip (although it may very well be buggy), but that I had never enabled wpa_supplicant to handle tkip protocol.

I re-emerged wpa_supplicant with the tkip use variable, and then reset the router to it's recommended AES/TKIP setting. I can log in without any issue now.
_________________
Casey Bralla
Chief Nerd in Residence
The NerdWorld Organisation

[NeddySeagoon]

Vorlon,

tkip is not buggy. It no longer provides any security worth having.
It was OK but its been overtaken by cryptoanalysis and advances in computing power.

At one time WEP was recommended. Then WPA/TKIP. Now nothing less than WPA2 will do. WPA3 is preferred.

Gentoo recently made -tkip the default, so there has been a bit of this on the forums.
Only use tkip if you have devices that do not support WPA2.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.