[Mailman-Users] Restrict Mass Subscription

enyc at sheer.us enyc at sheer.us
Sat Feb 12 05:08:34 CET 2005

> >  I would like them to be informed that the "www.list.org" web-server
> >    appears to be behind a broken firewall or router that discards packets
> >    from people using TCP_ECN extension....  I.e. linux 2.4 or 2.6
> >    kernel's default configuration.  Some *BSD variants include ECN
> >    with a 'fallback' mechanism so that such users can still connect,
> >    just ..slowly.. in this circumstance.
> 	I haven't heard of any other complaints of this sort, and this is 
> a pretty heavily trafficked machine, especially by people running 
> various distributions of Linux (both being GNU code and all).
Well, as I said, Most distributions turn off "tcp_ecn" at boot-time
  because of the broken-sites out-there.
> 	However, if you can demonstrate the problems with tcpdump or 
> other packet sniffing/capture tools, I'm sure that this is something 
> they will check into.
Urrm. I //can// arrange to make extra logs etc..
Though really I'd be logging 'nonexistant replies' !

The easiest way to demonstrate is turn on ECN yourself on a linux-2.4
  or linux-2.6 host.
Just "echo 1 > /proc/sys/net/ipv4/tcp_ecn" as root....
Then you will find list.org doesn't work, until you...
  "echo 0 > /proc/sys/net/ipv4/tcp_ecn" as root....

You can use a Free-Software-Program "tcptraceroute" to demonstrate
  the works/doesn't_work too...
Just  "tcptraceroute www.list.org 80" ... should 'work'
  and give "strongbadia.list.org ( [open]" etc.
Whereas  "tcptraceroute -E www.list.org 80" which behaves like
  linux-2.4/linux-2.6 with tcp_ecn on... currently just fails,
  giving "* * *" etc. [no answer].

> >  But still, this doesn't excuse that server at  [www.list.org,
> >    still breaks communication with TCP_ECN clients...
> 	I'm not sure who the day-to-day administrator is for that 
> machine.  I suspect you're going to have to report this problem to 
Will do... ;-).

> 	If you don't get a reply from Barry in a couple of days about 
> this issue (i.e., more than a canned auto-reply), let me know and 
> I'll try to find out who the appropriate person/people is/are.
Right, will see what happens.

Thankyou for helpful reply, at least.

--"enyc" <enyc at sheer.us>

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