The service provider doesn't use DHCP to hand out my static IPs. I was assigned them via an email. The DHCP server is on the DSL modem (not the DSLAM) and it hands out a single IP address in the 192.168.1.0/24 private range, namely 192.168.1.10. This is known as out-of-band management and only used for accessing the DSL modem itself and nothing else. The actual static addresses I'm assigned are in the public range while my DSL modem is supposedly set to bridging mode, i.e., it's not in the 10.0.0.0/8, 172.16.0.0/12 or 192.168.0.0/16 ranges.
-- Reality Artisans, Inc. # Network Wrangling and Delousing P.O. Box 565, Gracie Station # Apple Certified Consultant New York, NY 10028-0019 # Apple Consultants Network member < http://www.realityartisans.com> # Apple Developer Connection member Cell: (646) 327-2918 # Ofc: (212) 369-4876
If your service provider uses DHCP to hand out those “static” IPs, or their access gear allows that IP address to be entered (which is the case with our vendor’s gear), the access gear prevents someone else taking your static IP. Frank Yes, I understand why they gave me a /24 but with a /24, all it takes is for somebody else on the same subnet to accidentally (not intentionally or maliciously for obvious reasons) take my static IP and thus blow me out of the water without affecting them too much. I had this happen once. With a subnet between /24 and /30, they'd notice when their accidentally typo-ed IP address didn't work because it didn't match their gateway info. Reality Artisans, Inc. # Network Wrangling and Delousing
P.O. Box 565, Gracie Station # Apple Certified Consultant
New York, NY 10028-0019 # Apple Consultants Network member
<http://www.realityartisans.com> # Apple Developer Connection member Cell: (646) 327-2918 # Ofc: (212) 369-4876
PPPoE is used for authentication. If you have a static IP, they know who has it and you don't need authentication. PPPoE would be the termination point for the address, but since it will reside on your firewall, the modem needs to bridge the dsl network to the Ethernet network on the public side if the firewall They give you a /24 because they'd be burning up more IPv4 addresses giving you a smaller subnet. Other static IP customers use addresses in that subnet along with you. Jamie Montgomery | Comporium Network Facilities Engineering | Engineering Associate II www.comporium.com jamie.montgomery@xxxxxxxxxxxxx
The information contained in this e-mail message and any attachments thereto are confidential, privileged, or otherwise protected from disclosure, and are intended for the use of the individual or entity named above. Dissemination, distribution or copying of this message and any attachments by anyone other than the intended recipient, or an employee or agent responsible for delivering the message to the intended recipient, is prohibited. If you have received this communication in error, please immediately notify the sender by telephone or e-mail and destroy the original message, attachments, and all copies. No, the DSL modem is bridging, not routing. I've been assigned two static IPs (although they've given me a /24 net mask!!!) and my firewall is assigned one of them. The firewall is connected directly to the DSL modem by Cat6 patch cable. The other IP is unused (I use it for testing VPN configurations). I'm not sure but since the Broadxent Briteport is a PPPoE modem, I assume PPPoE. But the tech says that's not correct (WTF?). And he can't explain what they use. Sigh. Reality Artisans, Inc. # Network Wrangling and Delousing
P.O. Box 565, Gracie Station # Apple Certified Consultant
New York, NY 10028-0019 # Apple Developer Connection member Cell: (646) 327-2918 # Ofc: (212) 369-4876
Well if the tech can see stuff, its not what I thought might be the problem, which was PVC settings. But does your modem get an IP address, ie is it setup as a router or does your computer get the ip address? Are you using PPPoA/PPPoE etc? Some Comtrend modems can do a port mirror of the WAN (DSL) side.
Frank
-----Original Message-----
From: wireshark-users-bounces@xxxxxxxxxxxxx
[mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of Kok-Yong Tan
Sent: Tuesday, June 17, 2014 4:53 PM
To: Community support list for Wireshark
Subject: Re: [Wireshark-users] Using Wireshark for a DSL "link no surf"
problem
> On Jun 17, 2014, at 14:28, Jaap Keuter <jaap.keuter@xxxxxxxxx> wrote:
>
>> On 06/17/2014 08:42 PM, Kok-Yong Tan wrote:
>> Is it possible to use Wireshark to troubleshoot a DSL "link no surf"
problem? The ISP insists it's a CPE issue but the problem only started
after their Tier 1 tech monkeyed with the DSLAM and/or the CPE (remotely) in
some manner. I find it suspicious that the problem was intermittent packet
loss until they tinkered, whereupon the problem became a "link no surf"
issue (i.e., there's Layer 2 connectivity but zero Layer 3 traffic passing).
>
> Depends on what you can trace in the CPE, as in, how close to the DSL
interface.
> Otherwise you'll need capture hardware on the DSL....
>
> Good luck,
> Jaap
>
I can get up to the DSL modem itself. In hindsight, I'm thinking this isn't
going to be of much use and the only way to debug this is with capture
hardware on the DSL side as you suggested. Drat.
--
Sent from my iPad2 with greater chance of typographical, grammatical and
other disasters. Your indulgence is even more humbly requested.
--
Best regards / Mvh
Jan Pedro Tumusok
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