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Old 08-20-2014, 01:41 AM   #1
Registered: Dec 2013
Location: Italy
Distribution: Slackware
Posts: 487
Blog Entries: 13

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I've an internet connection to my ISP over something like (but not exactly) a hyperlan2 wireless link (the antenna understands pppoe), a homebrew WRAP based on this article that I wrote myself.
In short I've wlan0 and eth0 bridged to handle local traffic ( and eth1 dedicated for the pppoe link and firewall for masquerading outbound traffic and basic protection.
Bundled with internet my ISP gives me VOIP at an intresting rate (at least that holds true in my country but not for everywhere in the world). I was not told much about that. The antenna kit comes with a POE injector that has 4 plugs: power plug, ARJ45 that goes to antenna (ODU),ARJ45 for PPPOE and RJ11 for the phone (the power injector box does the VOIP stuff using unspecified protocol {SIP or god knows what else}). The label in the back of the OPE injector says "Airstrema 4001".

Lately I've been noticing that the antenna crashes braking my internet link status too often. Sometimes I haveto restart pppoe connection several times over short periods and at other times the link may stay up for a week or so.
The alternating periods ring a bell in my head that someone may be trying to hack into my home network and causing the antenna to crash.

I don't know much about the antenna itself: it was installed by ISP and all I was told is that it understands pppoe so the only thing I can do is look for suspicious stuff arriving ar my router ... and indeed I find some odd stuff arriving at my router:
here's the arp table cache stripped from the stuff coming from br0
? ( at 6c:62:6d:00:8d:27 [ether] on eth1
? ( at 00:0c:42:be:91:54 [ether] on eth1
? ( at 80:c1:6e:e9:a8:77 [ether] on eth1
? ( at 00:1b:fc:e4:99:31 [ether] on eth1
? ( at 20:89:84:83:74:0c [ether] on eth1
? ( at 10:fe:ed:a0:36:25 [ether] on eth1
? ( at 00:21:5d:1a:07:3a [ether] on eth1
? ( at 88:ae:1d:f6:6c:82 [ether] on eth1
? ( at 00:17:a4:17:af:b6 [ether] on eth1
? ( at 44:87:fc:a5:4c:b3 [ether] on eth1
? ( at d8:9d:67:c7:30:23 [ether] on eth1
Now how is it that those IP addresses make their way into my router's arp cache ? and moreover how is it that those ip addresses belonging private network addressing are reaching me from a WAN connection ?

Should I be asking the same questions to the ISP ?

I did a bit of extra research and it appears likely that my antenna uses a proprietary protocol EOLOWave (it boasts about getting the best from hperlan2, wimax and LTE, taking out all the stuff non needed for static links wireless links and achieving fantastic latency along with 4 times the spectral efficiency of hyperlan2).
Not sure if this is any help tough !

I got back to work and showed my question to a colleague in the NOC group and he told me that probably those are dew to arp announcements/requests reaching my antenna from other antennae connected to the same BTS ... and I get to see them on my router because pppoe works between layer 2 and 3.
That could be good for explaining how the MACs get in mt router's arp cache but it's still not satisfactory as to why other antennae should be sending arp announcements/requests on a WAN link with private subnet IP ?
Maybe misconfiguration on the other link side ? or is it malicious intent ?

Last edited by unSpawn; 08-21-2014 at 06:54 PM. Reason: //Retain 0-reply state


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