Mailinglist Archive: opensuse (4570 mails)
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Odd network behavior--suggestions?
- From: Simon Roberts <thorpflyer@xxxxxxxxx>
- Date: Thu, 24 Nov 2005 17:53:05 +0000 (UTC)
- Message-id: <20051124175245.93962.qmail@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Hi all,
I thought I understood networking (at least reasonably well) until now,
but I'm
staying in a hotel using my SuSE 9.3 laptop as a client to their
wireless LAN and
am seeing behavior that's making me doubt my sanity.
I turn on and tell netgo to connect to an open wireless network, which
it does.
My wireless interface gets configured (as 192.168.1.131 as it happens),
the default
route and DNS both are pointed at 192.168.1.1, so I'm assuming it's a
very simple
configuration like most the boxes one might use at home (Linksys, or
similar--if
it was Belkin it would be 192.168.2.1 I believe :)
Anyway, I do this, and I can connect to google.com and some other sites
OK. However,
some sites, probably 2/3 of all sites I've tried, and 99% of the more
obscure ones
(e.g. publib.boulder.ibm.com and theserverside.com--not sites that one
might expect
to be filtered) either come back immediately claiming they refused the
connection,
or they just time out. I ran ethereal and noticed that the refusals are
coming in
as those "unreachable" packets (they're ICMP aren't they?) with the
"administratively
cancelled" (or similar) flag set. The ones that time out just time out.
There
doesn't appear to be a rhyme or reason as to which will be refused and
which will
time out, and this seems to change from time to time. E.g. when I
arrived, I got
immediately rejected by both Earthlink's web-based mail site and by
mail.yahoo.com
(but not by yahoo.com itself). Later that night, earthlink started
working, and
yahoo disappeared entirely. Now they're both unavailable again.
Oh to add to the info, there's a wire-connected machine available for
public use
in this hotel's lobby, and it seems to be able to connect to pretty
much anything.
Once in a while it get's blown off, but no more than is a believable
rate for the
Internet as a whole.
But to add to the confusion, the IP addresses from the local DNS don't
always agree
with those I get from home. (I managed to connect to my home system
usins ssh, and
read email from there! While I was at it, I noticed that the dns
results for many
inaccessible sites were different.) That could be dynamic load
balancing at work,
but yesterday I tried to connect to my own system and the address was
total nonsense.
Could this be some strange attempt at filtering being done by the
hotel? Or a bizzare
effect of a massively overloaded, or interference-prone, wireless
infrastructure,
someone in the hotel doing strange things to me (my firewall is
running, and I didn't
see lots of unrecognizable traffic with ethereal), or a prelude to
martian invasion.
Or, something else I should know about?
Cheers
Simon
"You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions." Naguib Mahfouz
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
I thought I understood networking (at least reasonably well) until now,
but I'm
staying in a hotel using my SuSE 9.3 laptop as a client to their
wireless LAN and
am seeing behavior that's making me doubt my sanity.
I turn on and tell netgo to connect to an open wireless network, which
it does.
My wireless interface gets configured (as 192.168.1.131 as it happens),
the default
route and DNS both are pointed at 192.168.1.1, so I'm assuming it's a
very simple
configuration like most the boxes one might use at home (Linksys, or
similar--if
it was Belkin it would be 192.168.2.1 I believe :)
Anyway, I do this, and I can connect to google.com and some other sites
OK. However,
some sites, probably 2/3 of all sites I've tried, and 99% of the more
obscure ones
(e.g. publib.boulder.ibm.com and theserverside.com--not sites that one
might expect
to be filtered) either come back immediately claiming they refused the
connection,
or they just time out. I ran ethereal and noticed that the refusals are
coming in
as those "unreachable" packets (they're ICMP aren't they?) with the
"administratively
cancelled" (or similar) flag set. The ones that time out just time out.
There
doesn't appear to be a rhyme or reason as to which will be refused and
which will
time out, and this seems to change from time to time. E.g. when I
arrived, I got
immediately rejected by both Earthlink's web-based mail site and by
mail.yahoo.com
(but not by yahoo.com itself). Later that night, earthlink started
working, and
yahoo disappeared entirely. Now they're both unavailable again.
Oh to add to the info, there's a wire-connected machine available for
public use
in this hotel's lobby, and it seems to be able to connect to pretty
much anything.
Once in a while it get's blown off, but no more than is a believable
rate for the
Internet as a whole.
But to add to the confusion, the IP addresses from the local DNS don't
always agree
with those I get from home. (I managed to connect to my home system
usins ssh, and
read email from there! While I was at it, I noticed that the dns
results for many
inaccessible sites were different.) That could be dynamic load
balancing at work,
but yesterday I tried to connect to my own system and the address was
total nonsense.
Could this be some strange attempt at filtering being done by the
hotel? Or a bizzare
effect of a massively overloaded, or interference-prone, wireless
infrastructure,
someone in the hotel doing strange things to me (my firewall is
running, and I didn't
see lots of unrecognizable traffic with ethereal), or a prelude to
martian invasion.
Or, something else I should know about?
Cheers
Simon
"You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions." Naguib Mahfouz
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
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