[SATLUG] OT(?sorta) Linksys WCG200 - DHCP wrong (or bad) address with routing and NAT turned on

ed horned0wl93 at gmail.com
Mon Mar 31 08:33:27 CDT 2008


Jennie Haywood wrote:
> On Sun, Mar 30, 2008 at 2:54 PM, ed <horned0wl93 at gmail.com> wrote:
>   
>> Jennie Haywood wrote:
>>  >
>>  > hmm.... I'm getting the 72.48.68 and the 66.90.246 networks.
>>  > One of the things I tried was setting up the 72 address they were
>>  > sending me with a network mask of 255.255.254.0, which is the netmask
>>  > that they are using on the 66 network. It looks like they are using
>>  > the last 254 number of the subnet as the default gateway so put that
>>  > in.   That didn't work.
>>  >
>>  >
>>  Ok, Jeannie...  It looks like we're at least back in the same network,
>>  as you might see below, with the 72.48.68.xx address being the major
>>  trunk (Grandecom-market03-01), and the 66.90.246.xx being the local
>>  network (SM hub, SA Net).  Its possible that the local DHCP server (69)
>>  is wonky in some way, and either sending or defaulting DHCP requests
>>  up-channel.  If that's the case, the up-channel DHCP server (72)
>>  wouldn't know what to do with you (you're not at the right level on its
>>  routing table), and might either reject or ignore you  -- its hard to
>>  tell... Maybe this is some ammunition you could take back to them?
>>
>>  > 72.48.68.XX
>>  >
>>  > Grande Communications Networks, Inc. GRANDECOM-05 (NET-72-48-0-0-1)
>>  >                                   72.48.0.0 - 72.48.255.255
>>  > Grande Communications SAN ANTONIO HUB 1 GRANDECOM-MARKET03-01
>>  > (NET-72-48-68-0-1)
>>  >                                   72.48.68.0 - 72.48.69.255
>>  >
>>  >
>>  > 66.90.246.XX
>>  >
>>  > OrgName:      Grande Communications Networks, Inc.
>>  > OrgID:            GCNI
>>  > Address:        401 Carlson Cir
>>  > City:               San Marcos
>>  > StateProv:     TX
>>  > PostalCode:   78666
>>  > Country:        US
>>  >
>>  > NetRange:   66.90.128.0 - 66.90.255.255
>>  > CIDR:           66.90.128.0/17
>>  > NetName:    GRANDECOM-01
>>  > NetHandle:  NET-66-90-128-0-1
>>  > Parent:         NET-66-0-0-0-0
>>  > NetType:        Direct Allocation
>>  > NameServer: NS1.LSN.NET
>>  > NameServer: NS2.LSN.NET
>>  > Comment:      ADDRESSES WITHIN THIS BLOCK ARE NON-PORTABLE
>>  > RegDate:        2001-03-29
>>  > Updated:        2003-06-20
>>  >
>>  > OrgAbuseHandle: ABUSE153-ARIN
>>  > OrgAbuseName:   Abuse
>>  > OrgAbusePhone:  +1-512-878-4000
>>  > OrgAbuseEmail:  abuse at grandecom.com
>>  >
>>  > OrgTechHandle: IPSER2-ARIN
>>  > OrgTechName:   IP Services
>>  > OrgTechPhone:  +1-512-878-4000
>>  > OrgTechEmail:  ipservices at grandecom.com
>>  Whaddya think?
>>
>>     
>
>
> Thank you!  What's interesting is that the reported DHCP server for
> that 66 network is at 192.168.5.4.
>   
Likely correct, depending on the default factory spec internal IP
address of your router.  192.168.xx.xx is the block of IANA-assigned
addresses for a NATed Class C network -- what you would have inside your
router on your own network.  (What is your router's IP internal address?
What is your ISP-assigned IP address?)  Your router would be responsible
for assigning DHCP addresses within your network, and NATing them to
your external IP address. 

Note:  Factory spec (generalized) router internal IP addresses:  Belkin,
192.168.2.1; LinkSys, 192.168.1.1; Two-Wire [AT&T] 192.168.1.254; and so
on...  That would show up in Linux ACI, or in Windoze ipconfig /all as
your Default Route on any individual computer. 

Your DNS host should be either in the 69.xx.xx.xx or the 72.xx.xx.xx
networks, likely the latter.  Case in point:  My laptop's IP address is
192.168.1.xx, my router/IP address is 192.168.1.xx
(internal)/72.183.252.xx (ISP), and my DNS is up at 24.93.41.xx. 

You might want to check and see that your router has assumed proper
internal DHCP control, and isn't fronting one of your internal IP
addresses to the outside network...

Cheers;
Ed




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