diff --git a/docs/FAQ.xml b/docs/FAQ.xml index b5bf6ad83..67ae30230 100644 --- a/docs/FAQ.xml +++ b/docs/FAQ.xml @@ -2188,6 +2188,47 @@ We have an error talking to the kernel sch_sfq + +
+ (FAQ 97) I enable Shorewall traffic shaping and now my upload + rate is way below what I specified + + Answer: This is likely due to TCP + Segmentation Offload (TSO) and/or Generic Segmentation Offload (GSO) + being enabled in the network adapter. To verify, install the + ethtool package and use the -k command: + + root@gateway:~# ethtool -k eth1 +Offload parameters for eth1: +rx-checksumming: on +tx-checksumming: on +scatter-gather: on +tcp-segmentation-offload: on +udp-fragmentation-offload: off +generic-segmentation-offload: on +generic-receive-offload: off +large-receive-offload: off +ntuple-filters: off +receive-hashing: off +root@gateway:~# + + If that is the case, you can correct the problem by adjusting the + minburst setting in + /etc/shorewall/tcinterfaces (complex traffic shaping) or + /etc/shorewall/tcdevices (simple traffic shaping). We suggest starting + at 10-12kb and adjust as necessary. Example (simple traffic + shaping): + + #INTERFACE TYPE IN-BANDWIDTH OUT-BANDWIDTH +eth0 External 50mbit:200kb 5.0mbit:100kb:200ms:100mbit:10kb + + + Alternatively, you can turn off TSO and GSO using this command in + /etc/shorewall/init: + + ethtool -k ethN tso off gso off +