Stalled file transfers...

[rampguy]

I have been hitting my head against the wall about this for about 5 hours now...

I cannot transfer files from one computer to another across our wireless network. (it's a Linksys WRT54G)

For example, if I try to scp a file from one computer to another, it gets through about 800K, and then stalls. This happens again and again.

I have no idea what to fix. This is a problem across all our machines, though. It could be a wireless issue, but the computers are too far apart for me to plug them into the router's Ethernet ports.

Any ideas? The max file size I can transfer is about 700K, anything above that just freezes up (shows as "stalled" in Terminal). File sharing fares no better.

Thanks,

Alex

[trevor]

Have you tried changing the channel on your wireless router? Try the minimum or maximum channel. If you have interference in the radio frequency spectrum used by 802.11b and 802.11g, moving the channel might help.

Also, try turning off 2.4 GHz cordless phones, unplugging microwaves, etc. to see if you can eliminate the source of the problem. Of course, the source of the problem could be out of your control, too, like a neighbor, etc.

Also, the problem you are reporting sounds a bit like an issue with MTU, although I'm not sure how MTU problems would be applicable to LAN transfers.

Trevor

[rampguy]

Thanks Trevor. I have tried changing wireless channels. We have 2.4 GHz wireless phones that are supposedly "compatible" with wireless networks, and it's never caused an issue before. I'm able to use the internet in every other way, can download large files, etc...but just can't transfer files between machines.

Also, do you have any ideas in terms of how to set static wireless IP addresses? I want each computer on the network to have a fixed IP, not a dynamic one...but not sure how to accomplish that.

Alex

Quote: Originally Posted by trevor Have you tried changing the channel on your wireless router? Try the minimum or maximum channel. If you have interference in the radio frequency spectrum used by 802.11b and 802.11g, moving the channel might help. Also, try turning off 2.4 GHz cordless phones, unplugging microwaves, etc. to see if you can eliminate the source of the problem. Of course, the source of the problem could be out of your control, too, like a neighbor, etc. Also, the problem you are reporting sounds a bit like an issue with MTU, although I'm not sure how MTU problems would be applicable to LAN transfers. Trevor

[trevor]

Is your connection to the Internet through DSL? I'm still nagged by a feeling that this might be somehow oddly related to MTU, which is most often an issue with DSL. The oddity is that MTU problems are usually found with the WAN connection, not within the LAN.

Do you have a custom MTU set? System Preferences > Show: Built-in ethernet > Ethernet tab > Configure: Manually (Advanced) > Maximum Packet Size (MTU): Custom (and some number set that does not equal 1500)?

Setting static wireless IP addresses is easy. (The list might seem long, but it's repetitive.)

1. Turn off DHCP in your router, or else if you want to continue some DHCP for one class of computers, limit the DHCP server to a limited IP range within the given network mask. So if your network is 192.168.10.0 - 192.168.10.255, you can limit DHCP to 192.168.10.50-192.168.10.99.

2. On the computers in your LAN, set System Preferences > Network > Show: Airport > TCP/IP tab to:

a. Configure IPv4: Manually

b. IP Address: set to a unique IP address in the available IP space. So, to continue the example from above, if your DHCP server will be using IPs between 192.168.10.50 and 192.168.10.99, and your LAN is on 192.168.10.x, start manually giving IP addresses above 192.168.10.100. Keep a good record on a single piece of paper for which addresses go to which computers, and keep this record in a well-recognized place. You WILL need to refer to it later when you add or subtract computers on the network.

c. Subnet mask: set this manually. If you are using the examples given so far, the subnet mask will be 255.255.255.0

d. Router: enter the IP address of your router. Commonly, the number would end in .1, so to continue the example, it might be at 192.168.10.1.

e. DNS Servers: Set these manually too. If you forget to set these manually on all the LAN computers, you will have Internet access, but won't be able to use domain names, so most people will mistakenly think that you have no internet access. DON'T FORGET TO SET THIS.

f. Search Domains: optional

g. IPv6 Address: typically, you will want this set to OFF. Unless you know you need this, of course, but most people will not use this on a LAN.

3. Click Apply Now.

4. Repeat for all the computers on your LAN.

Trevor

[ph0enix]

Is the wireless network extended from a wired LAN? If so, I'd make sure that duplex mode/link speed is set correctly on all the systems.

[rampguy]

Thanks to everyone for their help.

The internet connection is DSL. However, I'm pretty sure this is a wireless problem. I went to Fry's and bought some really long CAT 5 cables, hooked up two computers to the router, and voila, file transfers started working right away (at least between 2 windows machines).

I am able to download and do everything else via wireless at breakneck speeds, so I have no clue why this one component (internal file transfers) works so poorly...or in this case, not at all.

I'm going to get 2 more long cables and try the Macs in the office next. This is really weird, though, because outside of this issue, we've never had any problems with our network.

On the static IP question: Which DNS servers should I use? The ones my DSL modem has (in this case, from SBC)?...These are set automatically when in DHCP mode, so I wasn't sure if there was some way to automatically grab them from the router when NOT in DHCP mode.

Thanks so much for your help!

Alex

Quote: Originally Posted by trevor Is your connection to the Internet through DSL? I'm still nagged by a feeling that this might be somehow oddly related to MTU, which is most often an issue with DSL. The oddity is that MTU problems are usually found with the WAN connection, not within the LAN. Do you have a custom MTU set? System Preferences > Show: Built-in ethernet > Ethernet tab > Configure: Manually (Advanced) > Maximum Packet Size (MTU): Custom (and some number set that does not equal 1500)? Setting static wireless IP addresses is easy. (The list might seem long, but it's repetitive.) 1. Turn off DHCP in your router, or else if you want to continue some DHCP for one class of computers, limit the DHCP server to a limited IP range within the given network mask. So if your network is 192.168.10.0 - 192.168.10.255, you can limit DHCP to 192.168.10.50-192.168.10.99. 2. On the computers in your LAN, set System Preferences > Network > Show: Airport > TCP/IP tab to: a. Configure IPv4: Manually b. IP Address: set to a unique IP address in the available IP space. So, to continue the example from above, if your DHCP server will be using IPs between 192.168.10.50 and 192.168.10.99, and your LAN is on 192.168.10.x, start manually giving IP addresses above 192.168.10.100. Keep a good record on a single piece of paper for which addresses go to which computers, and keep this record in a well-recognized place. You WILL need to refer to it later when you add or subtract computers on the network. c. Subnet mask: set this manually. If you are using the examples given so far, the subnet mask will be 255.255.255.0 d. Router: enter the IP address of your router. Commonly, the number would end in .1, so to continue the example, it might be at 192.168.10.1. e. DNS Servers: Set these manually too. If you forget to set these manually on all the LAN computers, you will have Internet access, but won't be able to use domain names, so most people will mistakenly think that you have no internet access. DON'T FORGET TO SET THIS. f. Search Domains: optional g. IPv6 Address: typically, you will want this set to OFF. Unless you know you need this, of course, but most people will not use this on a LAN. 3. Click Apply Now. 4. Repeat for all the computers on your LAN. Trevor

[bored28]

MTU would be an issue only if he was experiencing these problems while uploading and downloading in every event. rampguy....Does your wireless network have encryption enabled? that is, if you still have a wireless network

[rampguy]

Yes, we are using WEP. I know WEP sucks, but what sucks even more is getting WPA to work on some of our Windows machines.

We are not broadcasting SSID, using WEP 64 bit.

Thanks to everyone for their help!

Alex

Quote: Originally Posted by bored28 MTU would be an issue only if he was experiencing these problems while uploading and downloading in every event. rampguy....Does your wireless network have encryption enabled? that is, if you still have a wireless network

[bored28]

I would try connecting your computers wirelessly and sharing some files after DISABLING the WEP encryption. Make your network open for a short time, just to see if that works. I have a feeling that WEP might be causing some problems between machines. What are the machines that you have (specifically)?

[rampguy]

We have:

Intel iMac 17"
Mac PB Aluminum 15" 1.25GHz
Mac PB Aluminum 15" 1.5GHz
Windows XP Pro Dell * 4

I'll try disabling WEP...are there known problems with this?

Thanks!!!

Alex

Quote: Originally Posted by bored28 I would try connecting your computers wirelessly and sharing some files after DISABLING the WEP encryption. Make your network open for a short time, just to see if that works. I have a feeling that WEP might be causing some problems between machines. What are the machines that you have (specifically)?

[bored28]

Remember to restart all of your devices after you've disabled WEP. Are all of your machines running the latest version of OSX 10.4.6?