chaistt,

"BBraxton"'s advice about "too many firewalls" may be correct - but the only duplicate I'd suggest eliminating is ZoneAlarm and the XP firewall, if they're both enabled. There's plenty of unwanted traffic on most campus networks, and (as we've previously discussed, if I recall correctly!) having a small router between you and the campus network is a good idea. If you turn ZoneAlarm off (and also XP's firewall if it's on), does the login connection work?

Another possibility is "double NAT". If the campus DHCP server is giving out IP addresses on one of the "private networks" like 192.168 or 10, and the router's also assigning IP addresses on a private network, that sometimes causes strange problems. Can you check the WAN IP address, subnet mask, and gateway settings on the D-Link and also on your PC. If it's a NAT problem, that should be enough information to sort out the problem.

You have, I trust, checked for malware with Ad-Aware and Spybot!

Jim

Today my Internet Explorer caused problems ("would not work") and when I downloaded and installed FireFox 1.0 it works fine for all purposes, same connection(s).
I have read that only ONE firewall should be used. Since I support a graduate school's network and we have a network-wide firewall, you may be subjecting yours to four firewalls:
Windows XP
ZoneAlarm
hardware
Your school's
I would pick just one and turn all the rest off (disable).

Hi Jim, i do remember us talking about it. I'm using Win2000 which has not firewall built in so Zonealarm is running. The router has worked wonders as i have not had any intrusions since (according to zonealarm), apart from one which zonealarm stopped which was good (second line of defence is good!). I'll give the settings u gave a try. I'll keep u guys posted Thanks Steve

I am also interested in this thread because my daughter has Verizon DSL in DC with a D-Link DI-524 router and they cannot get hotmail or yahoo mail either.  W2k on the notebooks with the router set to "full stealth" (all the usual safeguards).  I'm not sure if it is Verizon blocking those email handlers or what....

I am near D.C. (Alexandria). Supporting many students, I see a lot of variations in networking, including non-Dell brands.

What Model is each of the notebook computers? Is the wireless built-in? If a PC card is added, what is the brand and model (of each)?

 

And BINGO it works

They e-mailing them if u it does not work for you model support@dlink.ca

Thanks for the info!  I have emailed her where she can get it and I'm watching for her on AIM so we can see if this fixes their problem.  Will update when I know.

Ok, I had her log in and change the MTU from 1500 to 1400 and it works for her also.  Thank you so much for passing that on! 

That's an odd one! Good for D-Link Support!

Ping can be used to figure out the MTU of a network path by using the "-f" and "-l" switches. "-f" sets the "don't fragment" bit in the packet, and "-l length" can set the packet's data length.

Example:

        
        c:\documents and settings\jimw\my documents>ping -f -l 1473 dslreports.com        
                
        Pinging dslreports.com [209.123.109.175] with 1473 bytes of data:        
                
        Packet needs to be fragmented but DF set.        
        Packet needs to be fragmented but DF set.        
        Packet needs to be fragmented but DF set.        
        Packet needs to be fragmented but DF set.        
                
        Ping statistics for 209.123.109.175:        
            Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),        
        Approximate round trip times in milli-seconds:        
            Minimum = 0ms, Maximum =  0ms, Average =  0ms        
                
        c:\documents and settings\jimw\my documents>ping -f -l 1472 dslreports.com        
                
        Pinging dslreports.com [209.123.109.175] with 1472 bytes of data:        
                
        Reply from 209.123.109.175: bytes=1472 time=140ms TTL=58        
        Reply from 209.123.109.175: bytes=1472 time=130ms TTL=58        
        Reply from 209.123.109.175: bytes=1472 time=140ms TTL=58        
        Reply from 209.123.109.175: bytes=1472 time=130ms TTL=58        
                
        Ping statistics for 209.123.109.175:        
            Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),        
        Approximate round trip times in milli-seconds:        
            Minimum = 130ms, Maximum =  140ms, Average =  135ms        
        c:\documents and settings\jimw\my documents>

So the MTU for that path is 1500. The actual packet length is 28 bytes more than the packet size.

1500 is the default MTU for most DSL routers, so clearly something's reducing that for the two cases that are now fixed.

Here's a DSL Reports article illustrating MTU discovery.

Jim

Nice work Jim.  I emailed her the link, and we'll see if she has time to do it.  Capable, yes; have the time, don't think so.  She's in season senioe year.  I'll probably try it when I get there Nov. 5th.

Thanks to all.  :smileywink:

One point to keep in mind is that the result of reducing the MTU below the minimum required for connections to work will be a reduction in overall throughput. The D-Link Support suggested value of 1400 may be smaller than the actual value that will prevent problems like this.

Ideally, the router will adapt, based on ICMP messages it receives, by reducing the MTU until the traffic can be successfully forwarded. Both Win2K and XP support a feature called "PMTU discovery", which is intended to adapt to situations like this. But if a router is the connection between the LAN and the Internet, the router either needs to support that feature, or it needs to have its MTU reduced manually until things work.

Note that the router's MTU setting needs to be 28 bytes more than the results reported by the "ping" experiment I described, since the router is looking at the entire packet size, which is the data size set by the "-l" subcommand to "ping" plus 28 bytes for the ICMP plus IP packet overhead.

This case needs to be added to all of our lists of things to check if SSL (https) traffic fails.

Jim

Yes the MTU was my problem a few years ago. I had to set the router at 1452. Pinged my brains out before I got the right numbers. Hotmail,Windowsupdate lots of places were hanging and never connecting. The Tweak Test  with a direct connection  will give you the right number +28 http://www.dslreports.com/tools Wish I had known about this link back then. 

maggie99635,

Isn't it annoyingly ironic that the advice everybody including me provides, "Install a router even if you have only one Windows system", creates a situation where this problem can happen? It's time to do some research on which SOHO routers do PMTU discovery!

Jim

The retailers make it sound so easy. Just hook it up and your zipping along.  I remember I knew nothing about networking or routers but I WANTED  them . My ISP wouldn't even support routers so you couldn't ask them anything.  Now they do just not wireless.

PMTU discovery articles worth reading:

http://www.enterprisenetworksandservers.com/monthly/art.php/120
http://www.netheaven.com/pmtu.html
http://mail-index.netbsd.org/tech-net/1997/07/15/0007.html
http://www.pointless.net/~jasper/consume/docs/my-docs/mtu.html

No insight yet into which SOHO routers actually support this.