One of my customers had a problem only with W2K machines and DHCP. His
NT4.0 and 98 machines didn't need port fast. Possibly W2K has less of a
delay between loading the lan driver (and activating the link) and looking
for a DHCP server? Or maybe they were just faster machines. Or maybe W2K
has a shorter timeout for the DCHP lease request? Anyway, I've been using
portfast on almost all workstation ports for the past few months.
Thanks,
Chuck Church
CCNP, CCDP, MCNE, MCSE
Sr. Network Engineer
Magnacom Technologies
140 N. Rt. 303
Valley Cottage, NY 10989
845-267-4000 x218
-----Original Message-----
From: Scott Morris [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 01, 2001 4:44 PM
To: 'Chuck Church'; ''Ccielab' (E-mail)'; 'Cisco@Groupstudy. Com
(E-mail)'
Subject: RE: Portfast
It's not specific to Windows 2000 machines... Any machine that needs DHCP
and boots up with any speed (less than 50 seconds), or any machine running a
novell client where it would try a GetNearestServer and find nothing....
Scott
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Chuck Church
Sent: Thursday, March 01, 2001 4:22 PM
To: 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail)
Subject: RE: Portfast
If this bdpu guard works as it supposed to, I'll definitely use it. Windows
2000 machines seem to need portfast for DHCP, and almost all Windows
machines need it for IPX. I've always pointed out to the customer about
NEVER connecting other layer 2 devices to the ports I configured portfast
on. This is good insurance.
Chuck Church
CCNP, CCDP, MCNE, MCSE
Sr. Network Engineer
Magnacom Technologies
140 N. Rt. 303
Valley Cottage, NY 10989
845-267-4000 x218
-----Original Message-----
From: Latimer, Keith [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 01, 2001 11:13 AM
To: 'McCallum, Robert'; 'John Chang'; 'Ccielab' (E-mail);
Cisco@Groupstudy. Com (E-mail)
Subject: RE: Portfast
Check out the new portfast bpdu guard feature. It can shut down ports that
have portfast enabled when detecting bpdus on the line.
Keith
-----Original Message-----
From: McCallum, Robert [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 01, 2001 10:44 AM
To: 'John Chang'; 'Ccielab' (E-mail); Cisco@Groupstudy. Com (E-mail)
Subject: RE: Portfast
No,
The problem occurs if he creates a loop i.e. you have a main switch a cable
from the main switch goes to user A. User A decides to connect a hub and a
few terminals - Outcome fine. User B then says hey user A can you access
those terminals and the main network. User A says yeah how do you want to
connect? User A says yes and inadvertently patches his own pc and the
original connection that was from him to the main switch outcome is now main
switch has 2 connections to the minihub. NOW spanning tree goes oh my and
recalculates - outcome 30 second outage for everyone on that vlan. Then the
users go home, switch off their kit and go to the pub.
Next day..... The mini hub is switched back on - because portfast is enabled
the ports go whoosh straight into forwarding mode - result - spanning tree
goes oh my!! and recalculates.
Outcome ------ You and every other support member run about like loonies
trying to find this fault which occurs only when the user decides to switch
on his equipment.
-----Original Message-----
From: John Chang [mailto:[EMAIL PROTECTED]]
Sent: 01 March 2001 15:34
To: McCallum, Robert
Subject: RE: Portfast
Let me see if I got this correct. If he only connects one mini-hub or
mini-switch it is OK to have portfast on on the main switch. If he then
connects another mini-hub or mini-switch onto the first mini-hub or
mini-switch than there will be a problem. But when you connect 2 mini-hubs
aren't you just extending the amount of ports and in a sense there is only
one virtual mini-hub?
At 03:24 PM 3/1/2001 +0000, you wrote:
>yes, but only if he then connects another link to another hub / switch and
>causes a bridging loop.
>
>-----Original Message-----
>From: John Chang [mailto:[EMAIL PROTECTED]]
>Sent: 01 March 2001 15:08
>To: [EMAIL PROTECTED]
>Subject: Portfast
>
>
>In the below website it says not to have portfast on if you connect
>switches, hubs, or routers. I understand that point but what if a user
>connected a mini-hub (Ex. Linksys EtherFast 8-Port 10/100 Desktop Hub)
>or unmanaged mini-switch (Ex. Farallon NetLINE 10/100 switch) so that he
>could connect multiple computers. Would this cause any problems? Thank
>you!
>
>
>http://www-1.cisco.com/warp/public/473/12.html
>
>Note: The portfast feature should never be used on switch ports that
>connect to other switches, hubs, or routers. These connections may cause
>physical loops
>and it is very important that spanning tree go through the full
>initialization procedure in these situations. A spanning tree loop can
>bring your network down. If portfast
>is turned on for a port that is part of a physical loop, it can cause a
>window of time where packets could possibly be continuously forwarded (and
>even multiply) in
>such a way that the network cannot recover.
>
>_________________________________
>FAQ, list archives, and subscription info:
>http://www.groupstudy.com/list/cisco.html
>Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
_______________________________________________________
To unsubscribe from the CCIELAB list, send a message to
[EMAIL PROTECTED] with the body containing:
unsubscribe ccielab
_______________________________________________________
To unsubscribe from the CCIELAB list, send a message to
[EMAIL PROTECTED] with the body containing:
unsubscribe ccielab
_______________________________________________________
To unsubscribe from the CCIELAB list, send a message to
[EMAIL PROTECTED] with the body containing:
unsubscribe ccielab
_________________________________
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
