| Author |
Message |
Guest
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 Posted:
Mon Oct 03, 2005 8:20 am Post subject:
College ethernet switch problems |
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Hi, I have a kind of middle ground knowledge of networks and have read
alot of the past two days but still have a few questions and thought id
ask the wizards. If im in the wrong group any help or advice where to
go would be greatly appreciated. Ok, my school has a somewhat normal (i
assume) network, which always works straight from the jack to a NIC,
and until 2 days ago, through my netgear wireless router. All of a
sudden our internet went down and after checking my routers settings it
couldnt get an IP from the network. There are signs all over saying NO
ROUTERS, which i dismissed because i didnt think it would matter or a
modern network. But anyways, so i pulled in a buddies 4-port switch,
plugged it in and viola, internet was back. Had to return it as i was
just doing troubleshooting. After being pissed my router no longer
worked i turned off its DHCP server to, i thought, make it act as a
switch. Well that didnt work either. Then, today a friend gave me a
linksys 16 port workgroup switch, model:EZXS16W, hoping it would work,
but after trying all kinds of combos of plugging, if i ran it from the
wall into port 16/uplink, id get the top light, the link/act light to
light and blink, but not the 100 light or Full Duplex/Collision light.
Then when i plug a computer in all three lights turn on for it, but it
sits at aquiring IP and then goes to limited or no activity. Is there a
way to fix it without buying anything new? (did i mention im a college
student? :) or am i screwed? Thanks for your help! |
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Michael Roberts
Guest
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| Posted:
Mon Oct 03, 2005 4:20 pm Post subject:
Re: College ethernet switch problems |
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It is very easy to block MAC address prefixes in a DHCP server. More
than likely, your sys admins of the DHCP servers have found relevant MAC
address prefixes for the popular broadband routers and denied them from
obtaining IP addresses.
Do not be afraid to ask questions, and be honest. Give your helpdesk a
call, and request to talk with someone in networking. Do not assume
that you can get fancy with some setup and skirt by under the radar. If
your network admins are smart, then can detect all kinds of anomalies
like downstream switches/hubs, broadband routers, wireless APs, etc.
More than likely, you are paying a port fee, which may be built in to
your room rate. That port fee is probably for one port, and the network
in your building may only be designed to support one host or two hosts
per room. Call and ask.
-mike
phildman14@yahoo.com wrote:
| Quote: | Hi, I have a kind of middle ground knowledge of networks and have read
alot of the past two days but still have a few questions and thought id
ask the wizards. If im in the wrong group any help or advice where to
go would be greatly appreciated. Ok, my school has a somewhat normal (i
assume) network, which always works straight from the jack to a NIC,
and until 2 days ago, through my netgear wireless router. All of a
sudden our internet went down and after checking my routers settings it
couldnt get an IP from the network. There are signs all over saying NO
ROUTERS, which i dismissed because i didnt think it would matter or a
modern network. But anyways, so i pulled in a buddies 4-port switch,
plugged it in and viola, internet was back. Had to return it as i was
just doing troubleshooting. After being pissed my router no longer
worked i turned off its DHCP server to, i thought, make it act as a
switch. Well that didnt work either. Then, today a friend gave me a
linksys 16 port workgroup switch, model:EZXS16W, hoping it would work,
but after trying all kinds of combos of plugging, if i ran it from the
wall into port 16/uplink, id get the top light, the link/act light to
light and blink, but not the 100 light or Full Duplex/Collision light.
Then when i plug a computer in all three lights turn on for it, but it
sits at aquiring IP and then goes to limited or no activity. Is there a
way to fix it without buying anything new? (did i mention im a college
student? :) or am i screwed? Thanks for your help!
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Guest
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| Posted:
Tue Oct 04, 2005 1:50 am Post subject:
Re: College ethernet switch problems |
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Thanks Mike, I called them and they ran through everything they could
and we think its a broken switch. It shows a link and activity, but
wont go full duplex, and the computers connected all say limited or no
activity. So now I go and buy a switch. One thing that has been
bothering me is why wouldnt they want routers on the network? What
detrement does that have on the network? Is it just because you
disguise your IP? Thanks! |
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Wayne
Guest
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| Posted:
Tue Oct 04, 2005 2:45 am Post subject:
Re: College ethernet switch problems |
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<phildman14@yahoo.com> wrote in message
news:1128372658.724690.197880@o13g2000cwo.googlegroups.com...
| Quote: | Thanks Mike, I called them and they ran through everything they could
and we think its a broken switch. It shows a link and activity, but
wont go full duplex, and the computers connected all say limited or no
activity. So now I go and buy a switch. One thing that has been
bothering me is why wouldnt they want routers on the network? What
detrement does that have on the network? Is it just because you
disguise your IP? Thanks!
|
It could be a legal thing. College networks generally have LOTS of p2p
traffic. If a dorm room is masked by a broadband router, it's possible that
either dorm-inhabitant could have innitated an illegal download from the
routers "outside" address, not to mention any wireless clients that could
have latched on to the thing (if it's a wireless router). |
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glen herrmannsfeldt
Guest
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| Posted:
Tue Oct 04, 2005 8:20 am Post subject:
Re: College ethernet switch problems |
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Wayne wrote:
| Quote: | phildman14@yahoo.com> wrote in message
news:1128372658.724690.197880@o13g2000cwo.googlegroups.com...
(snip)
One thing that has been
bothering me is why wouldnt they want routers on the network? What
detrement does that have on the network? Is it just because you
disguise your IP? Thanks!
It could be a legal thing. College networks generally have LOTS of p2p
traffic. If a dorm room is masked by a broadband router, it's possible that
either dorm-inhabitant could have innitated an illegal download from the
routers "outside" address,
|
Not very convincing. First, if the router is used by just one person,
then you know who it is. They should use managed switches so they can
track things down to the port, independent of MAC address, and supply
enough ethernet ports per room so that each occupant has a port that
they are responsible for.
| Quote: | not to mention any wireless clients that could
have latched on to the thing (if it's a wireless router).
|
This is more convincing, though the rule should then be no wireless
routers, or at least no wireless routers without encryption turned on.
Note that both hosts and routers can easily change their MAC address,
so identifying hosts or routers based on that doesn't make much sense.
Many routers are just linux machines inside. I have heard that some
linksys routers can have linux downloaded into, and run just like any
other linux host.
Much worse than routers is most versions of windows with sharing
enabled, or with older versions even with it disabled.
-- glen |
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Wayne
Guest
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| Posted:
Tue Oct 04, 2005 8:20 am Post subject:
Re: College ethernet switch problems |
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"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote in message
news:79WdnYir8u1Qnt_eRVn-hA@comcast.com...
| Quote: | Wayne wrote:
phildman14@yahoo.com> wrote in message
news:1128372658.724690.197880@o13g2000cwo.googlegroups.com...
(snip)
One thing that has been
bothering me is why wouldnt they want routers on the network? What
detrement does that have on the network? Is it just because you
disguise your IP? Thanks!
It could be a legal thing. College networks generally have LOTS of p2p
traffic. If a dorm room is masked by a broadband router, it's possible
that either dorm-inhabitant could have innitated an illegal download from
the routers "outside" address,
Not very convincing. First, if the router is used by just one person,
then you know who it is. They should use managed switches so they can
track things down to the port, independent of MAC address, and supply
enough ethernet ports per room so that each occupant has a port that
they are responsible for.
|
You don't know that only one person is behind the router. We did this when
I was at school - we had to pay per activated port, so my roommate, the 2
neighbors and I pitched in on the per-semester bill and split the cost of
the router and we shared one connection. |
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Robert Redelmeier
Guest
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| Posted:
Tue Oct 04, 2005 4:20 pm Post subject:
Re: College ethernet switch problems |
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phildman14@yahoo.com wrote:
| Quote: | Thanks Mike, I called them and they ran through everything
they could and we think its a broken switch. It shows a link
and activity, but wont go full duplex, and the computers
connected all say limited or no activity.
|
Since it was once working, I can only assume some sort of config
change. Since you didn't do it, it must have been upstream.
| Quote: | So now I go and buy a switch. One thing that has been
bothering me is why wouldnt they want routers on the
network? What detrement does that have on the network? Is
it just because you disguise your IP? Thanks!
|
You don't really disguise your IP, but you could shovel more
traffic through a router. For some reason (paranoia perhaps
justified about wireless) they really don't want routers.
You really should comply. It is their network.
Well, detecting and blocking routers isn't exactly easy and
the skule's netadmins may not have the skills. But forcing
all ports to 100 is simpler and will block out many SOHO routers
because their WAN uplink ports are only 10baseT.
-- Robert |
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Michael Roberts
Guest
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| Posted:
Tue Oct 04, 2005 4:20 pm Post subject:
Re: College ethernet switch problems |
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Students are now bringing desktops, laptops, Playstations, XBoxes, blah,
blah... One ethernet port, per student, is unrealistic in many cases.
We are not concerned about billing because a student pays for the port
whether they use it or not because it is built into their room rate. We
have told students that NAT routers are okay, but NAT routers with the
wireless option are not okay. We require MAC address registration, so
even routers have to be registered devices. Registering devices like
Playstations and XBoxes can be problematic, so we encourage students to
use NAT routers for connectivity to those devices.
It is too complicated to try and explain how to enable wireless
encryption on every vendor's broadband wireless router. Eventually we
will provide wireless coverage to the reshalls, and we will deploy rouge
detection and containment.
Wayne wrote:
| Quote: | "glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote in message
news:79WdnYir8u1Qnt_eRVn-hA@comcast.com...
Wayne wrote:
phildman14@yahoo.com> wrote in message
news:1128372658.724690.197880@o13g2000cwo.googlegroups.com...
(snip)
One thing that has been
bothering me is why wouldnt they want routers on the network? What
detrement does that have on the network? Is it just because you
disguise your IP? Thanks!
It could be a legal thing. College networks generally have LOTS of p2p
traffic. If a dorm room is masked by a broadband router, it's possible
that either dorm-inhabitant could have innitated an illegal download from
the routers "outside" address,
Not very convincing. First, if the router is used by just one person,
then you know who it is. They should use managed switches so they can
track things down to the port, independent of MAC address, and supply
enough ethernet ports per room so that each occupant has a port that
they are responsible for.
You don't know that only one person is behind the router. We did this when
I was at school - we had to pay per activated port, so my roommate, the 2
neighbors and I pitched in on the per-semester bill and split the cost of
the router and we shared one connection.
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glen herrmannsfeldt
Guest
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| Posted:
Wed Oct 05, 2005 8:20 am Post subject:
Re: College ethernet switch problems |
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Robert Redelmeier wrote:
(snip)
| Quote: | Well, detecting and blocking routers isn't exactly easy and
the skule's netadmins may not have the skills. But forcing
all ports to 100 is simpler and will block out many SOHO routers
because their WAN uplink ports are only 10baseT.
|
The linksys WRT54G has a 10/100 half/full duplex WAN port.
It can also run linux such that it should be technically
a computer and not a router. (It may be that they run linux
out of the box, but there are also versions that one can
download to them.)
Though a 10/100 switch should be about $5 these days
used or on sale new. Not more than $10, anyway.
Find one on eBay if your store doesn't have one.
-- glen |
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