ROUTER PROBLEM - MTU "on" conflicts with Counterstrike, MTU "off" conflicts with FTP uploading?

[udonoogen]

we share an dsl internet connection upstairs and there has been a slight problem with the router. it's a linksys router and it's regarding the MTU. when it's on (and set to 576) i can upload normally to a specific FTP, when it's off i can't upload (but the guys across the hall can play counterstrike just fine. as you can imagine, when this is switched on (even when i'm not uploading) their ping goes up and they cant play. is there a solution to this? i've tried upping the MTU but that results in the inability to upload as well.

 

[udonoogen]

SPI: Disable
Block WAN Request: Disable
Multicast Pass Through: Enable
IPSec Pass Through: Enable
PPTP Pass Through: Enable
Remote Management: Disable
Remote Upgrade: Disable
MTU: Enable/Disable Size: 576

are these right? we're just sharing a dsl connection. what is optimum? this is a linksys router. thanks in advance

 

[sml]

MTU is maximum transmission unit, or how many bytes a packet can contain before it becomes fragmented into another packet. the default for ethernet is 1580 [1500 data bytes + 80 for the header info] - this is how all your client systems should be set. i'm not sure what you mean by turning the MTU setting 'off' but the ftp uploading could be an issue with 20/tcp [ftp-data] and 21/tcp and some issues with fragmented packets, or perhaps timeouts when uploading a file of a decent size. can you change the setting to a numerical value? try 768, or 1024 and see how that works for you.

 

[JackMDS]

576 is the default MTU for Dialup Modem. Depending on the rest of your setting 1492 is usually the efficient MTU for DSL.

 

[udonoogen]

1492 doesnt work but 576 and 1024 do. i think both limit the ping on my housemates' counterstrike game so theyd rather turn it off. i suspect 1492 would be better but i cant get it to work. any thoughts?