Need help with an issue on our work network

[Thirteenva]

I work for a business that is on a university campus. For two years I've been working on the network (dedicated T1 line from our building) with macs for over 2 years. Starting last month I noticed a slowdown in my outbound bandwidth. I had trouble downloading things off of my work G5 from home using my powerbook, and at work I have issues uploading files to various offsite servers. In fact it seems that I can't upload at a rate any faster than 10kb/s

I can confirm the following.

The issue is not my cable connection from home.

The issue does not appear to be the network card on the G5, I took the computer home and it works fine.

Also I brought in my laptop and connected it to a different jack on the network and got the same results, where my upstream was slow.

The PC's on the network are not experiencing this issue.

It is only an upstream bandwidth problem, can receive/download fine.


I contacted the system admin at the university who insists he's made no network changes despite the fact that everything worked fine until march, when I believe a firewall change took place.

I'm hoping someone can recommend a utility or some way that i can help the system admin solve the issue. Thanks.

 

[baummer]

Where on campus are you connecting from? I know my university limits the amount of in/out traffic depending on different areas of the campus. Could be the case in your situation.

 

[jeremy.king]

I'll also put my money on that fact that uploads are throttled on that network. Keeps people from running "servers" - Although the PCs comment is interesting. Do they PCs authenticate to a Domain Controller? If so, perhaps they limit "guest" access - which is what your mac would be running since you don't authenticate to the network.

 

[Thirteenva]

Where on campus are you connecting from? I know my university limits the amount of in/out traffic depending on different areas of the campus. Could be the case in your situation.

We're on a different subnet than the students, we're only on the University network because my business rents office space from the university.

 

[Thirteenva]

I'll also put my money on that fact that uploads are throttled on that network. Keeps people from running "servers" - Although the PCs comment is interesting. Do they PCs authenticate to a Domain Controller? If so, perhaps they limit "guest" access - which is what your mac would be running since you don't authenticate to the network.

Not the case here. We are a business not students, the university supplies us with internet connection because my business rents the office space from them. I have contacted the system admin who says uploads are not throttled. Plus as I stated, the pc's on the network do not have this issue. Also we have 3 servers here that do not suffer from the issue either(we are allowed to run servers so thats not a reason to throttle my company's bandwidth).

The only two machines having upload issues are the Macs which are limited to 20kbs or about 8kb/s. This was not an issue until last month.

 

[jeremy.king]

The only two machines having upload issues are the Macs which are limited to 20kbs or about 8kb/s. This was not an issue until last month.

You're convinced its the macs, I'm convinced its the network. I'll just agree to disagree. Definitely post if you find the culprit.

 

[Thirteenva]

You're convinced its the macs, I'm convinced its the network. I'll just agree to disagree. Definitely post if you find the culprit.

I agree its a network issue, however it cannot be reproduced on any of the 8 windows xp machines in the office. So whatever the issue on the network is, it is only affecting my macs thus making it mac specific. Wouldn't you agree?

 

[jeremy.king]

I agree its a network issue, however it cannot be reproduced on any of the 8 windows xp machines in the office. So whatever the issue on the network is, it is only affecting my macs thus making it mac specific. Wouldn't you agree?

Well, depends on if the windows boxes are configured to authenticate to the network. If they do - that may explain the seemingly mac specific throttling. A quick test is throw a PC on the network that not configured to authenticate to a domain server and see if is experiences slow uploads.

I often run into this as a consultant, as many times I bring my own laptop that isn't configured to be on the clients network. Many of our clients will throttle guest machines on their network (both u/l and d/l) so they don't consume too much bandwith. Its actually quite common.

 

[Toe]

I agree its a network issue, however it cannot be reproduced on any of the 8 windows xp machines in the office. So whatever the issue on the network is, it is only affecting my macs thus making it mac specific. Wouldn't you agree?

The only thing I know of that differentiates Macs from PCs on an IP network is "Spanning Tree." If the admin turned that on on the switches (or perhaps it is an option on the new firewall), it can cause problems for Macs. I don't know the specifics, but IIRC, it causes random, odd problems. Try some web searches if you want some detail.

Something to check into, at least.

But first, I do think kingjr3's recommendation about domain authentication is a good avenue to research. If they are controlling based on authentication, you should be able to set up the Macs with a similar configuration using Directory Access. Just be careful when using that program... there is a good reason that it requires you to re-authenticate every five minutes...

 

[Thirteenva]

Well, depends on if the windows boxes are configured to authenticate to the network. If they do - that may explain the seemingly mac specific throttling. A quick test is throw a PC on the network that not configured to authenticate to a domain server and see if is experiences slow uploads.

I often run into this as a consultant, as many times I bring my own laptop that isn't configured to be on the clients network. Many of our clients will throttle guest machines on their network (both u/l and d/l) so they don't consume too much bandwith. Its actually quite common.

Good suggestion. None of our windows machines are currently set up to authenticate to a domain. However, there are domains in use on the network but again, we're not using domains for our network.