Mac OS X 10.3.8 Special Report: Routers and slow network performance

March 2, 2005 12:48 AM PST

Some routers -- particularly a handful of models manufactured by NetGear -- can cause a reduction in network performance under Mac OS X 10.3.8. When this situation occurs, users can often resolve the issue by removing the offending router from the network set-up.

Potential solutions include:

Manually entering DNS numbers Some users have been able to reclaim lost network performance by manually entering DNS server addresses in the Network Pane of System Preferences. Many times your ISP's specific DNS addresses can be found in in the on-router configuration file, usually accessible via the URL "192.168.1.1." (check your router manual for more information).

MacFixIt reader Eric writes: "I've seen this problem with my Netgear WRG614v4. My guess is that the users having this problem are getting the DNS servers via DHCP. I've had success getting 'net speeds back up by manually typing in the DNS servers from my ISP on the clients. In the Netgear router's config page those IPs can be found in the Router Status area. I don't know why having a DNS supplied via DHCP is causing problems because the correct DNS servers show up in /etc/resolv.conf but manually typing in the DNS in the Network Prefpane fixes it."

Andy James writes: "I too have had issues with the 10.3.8 update and my Netgear MR814v2 router (on EarthLink DSL). I have tracked down the issue a bit, though -- it seems to be somehow related to the router's DNS proxy feature. By default, the router gives out its own address for all DHCP clients, then it seems to serve as a proxy for all DNS requests. If I hard-code the DNS addresses into the computer (not the router), I get better network performance than I have ever gotten with the router."

Jim Macak had similar results: My router is a Netgear MR814 v3 802.11b wireless router. My main Macintosh is actually on its network via Ethernet. My ISP is Roadrunner (in Wisconsin). After installing 10.3.8 (from 10.3.7, using Combo Updater and fixing permissions before and after) I could no longer send e-mail via Apple Mail. Recalling previously recommended fixes, I manually entered the ISP's DNS addresses into my Network configuration. This has fixed the problem. iChat and iTunes music store come up fine also, though I had not checked them for a 10.3.8 problem before entering the fix."

For more information on DNS connectivity issues, see this previous article.

Make sure your router's firmware updated Check your router manufacturer's Web site for the latest available firmware. In many cases, applying the latest release can resolve issues associated with incremental Mac OS X updates and Security updates.

MacFixIt reader Donald Latham had success with the application of new firmware: I noticed my wireless network slowed substantially at 10.3.7. I did all the tricks trying to speed it up. At Mac OS X 10.3.8 it seemed slow more and I had trouble getting to apple itunes store. I however upgraded to the latest v7 firmware (it ships with v3). In the NetGear notes there were some comments regarding network slowdown. It seems much snappier now [...]

Change to dynamic setting Most newer routers offer dynamic routing capability (a setting usually accessible via the browser's configuration page; LinkSys instructions, for instance, are here)

One reader writes: "I to have experienced the same PPoE issues with my router after the 10.3.8 update.(D-Link 804) Working with my ISP I discovered 2 things. First Rebuilding the TCP stack is the best corse of action (Creating a new location). This got me up and running at first. However, second and better option, if one has the option of FULLY DYNAMIC or PPoE connections through the ISP choose the FULLY DYNAMIC setting for one's router. I find the response is better than trying to get PPoE to efficiently connect since the 10.3.8 update (as well as now my ISP tries to recommend Dynamic setting to customers). As your one reader reported there seems to be significant lag in network connections and opening such programs as MAIL after the update. Since my IPS recommend I move to Dynamic connection things are once again 'Snappy.'"

Turn off WEP Security Though we can never recommend disabling wireless security measures, some MacFixIt readers report that turning off WEP protection on Wi-Fi routers resolved slow-down issues associated with Mac OS X 10.3.8.

Bruce Forsberg writes: "When I first purchased the NetGear router, I set it up with a WEP login. It was constantly slow and inconsistent. Last year I tried upgrading to the WGT624v2. It had the same sluggish performance as the MR814v2 or worse. I have since put the MR814v2 back into my network without any security and it performs well. I suggest that if Philip Chadwick is using a WEP login, try using the open network and see if the sluggishness goes away."

Power off all networking devices and your Mac Disconnecting power from all networking devices (router, network adapter [DSL, Cable]) and turning off your Mac, waiting a few minutes, then restoring power to all devices can sometimes trigger an alleviation of the speed bottleneck introduced with Mac OS X 10.3.8.

Creating a new network location Joe Boyer reports that his case of network slowness after updating to Mac OS X 10.3.8 was resolved by creating a new Network Location in the Network pane of System Preferences:

"I updated to 10.3.8 and my Internet DSL 1.5 Mbps download speed went to 1.3KB/sec, any slower and I would be traveling back in time. I installed the Mac OS X 10.3.8 combo updater to see if that cured it, it didn't. I e-mail my ISP but that will take forever for a reply. Then I remembered a little trick from MacFixIt. I put in a new location in the Network System {refs. That did the trick."
Setting a lower MTU rate MacFixIt reader Alan Knoepfler reports that setting the router MTU ( Maximum Transmission Unit) size to 1432 or lower resolves network slow-down issues.

Changing the MTU setting can be accomplished either through your router's configuration page (usually accessible via the URL 192.168.1.1.) or more easily with a shareware utility like IPNetTuner.

Knoepfler writes:

"I was advised by my ISP to further reduce my MTU size to 1432 and have had no problems since. Except for stalls with opening pages occasionally, but I think that is more a Safari issue. I still have the Netgear router and I'm still on PPPoA, however if this is phased out and only PPPoE is available I think I will be stuck as my DG814 does not work at all on that setting. The router is using the latest firmware from Netgear v4.10. It seems that there is an issue with the Netgear but to date I?m not sure what the kernel of the problem is, except that the router seems stable with MTU being set at 1432 ? I have access to internet and emails and the slowdown issue seems to have normalized, though can be erratic occasionally but this could be due to traffic."