04-15-2012 08:41:10 AM
Having a pretty awful week of connectivity issues... i lose my DSL connection totally multiple times a day.
I've had ATT dsl for years, and 6 months ago or so i switched to a UVERSE DSL plan (i'm still dry-loop dsl). My service has been rock solid for a very long time in two different locations. So it's amazing that the last week has been so terrible.
I've had a tech out and he measured the line where it hits the building and in my unit, and both show excellent throughput. the line is a little stressed, at nearly 100%, but this shouldn't, i'm told, cause these issues.
i'm starting to keep stats on how often i encounter issues, though i'm sure i'm missing some cuz i'm not constantly watching.
am there others in SF with similar issues?
04-15-2012 09:05:00 AM
I am in San Jose, and my problems began in mid-March, went away for 18 days and returned today. I sent this email to one of the support case owners with whom I'd corresponded last month. the bottom line is that, when the problem happens, the DSL doesn't come up in a way that actually passes traffic, and something upstream is sending IGMP packets (a protocol not needed for internet access on DSL or any other network) downstream to me at the same time.
When my DSL connection is stable, I see no IGMP at all. The reason I see this stuff is that I'm a network engineer, and in fact an escalation manager for SonicWALL, an internet security vendor purchased by Dell a few weeks ago. I've had this ATT Yahoo DSL line for 8 years, running our firewalls behind it for most of that time w/ very little trouble.
I hope this helps, YMMV - John
(I wrote to ATT suppot)
This is happening again today. I continued my captures and found no IGMP from your network for about 3 weeks, from March 28 until today, April 15. Attached are the latest captures.
I want to talk to your ATT DSL Escalations Manager in the next week or I'm seriously researching a drop of all of my phone / DSL services with you. We hate Comcast but we may have to use them for internet.
----- Forwarded Message -----
From: John Lasersohn
Sent: Wednesday, March 21, 2012 8:36 AM
Subject: ATT DSL - eeing IGMP sent from your network, associated w/ outages
ATT is sending IGMP down to my firewall from the modem (or upstream), and when it does, they seem to expect a response and take my DSL offline when it doesn't come: IP Type: IGMP(0x2), src=[192.168.0.1], Dst=[188.8.131.52]. sending screenshots, pcaps to L2 support now
Attached is a zip containing a pcap (capture) file and a screenshot.
The screenshot shows that the IGMP packets stopped coming in my firewall's capture at 7:54 AM and that my continuous pings have been up since then (roughly 1800 replies), with the clock showing about 30 minutes later (8:26 AM).
The capture was taken from my SonicWALL NSA-2400 firewall, while it was gathering data only when the source or destination IP address was 192.168.0.1 (the former IP address of my speedstream modem (4100 B model), which is now in bridging mode because I want the firewall doing NAT and VPN for me.