Inherited TZ500, slow / failing downloads.

Simon_Ward

Hi,

We have taken over a new client and inherited an TZ500. SonicOS Enhanced 6.5.2.1-31n

The client has reported intermittent download issues (they have a 100/100Mb ethernet), and indeed we witness downloads starting, sometimes very fast, then seem to stall, or then fail, or continue at a snails pace 156Kb for example. It's a small network, maybe 60 clients (inc peripherals), CPU@ 1.45% Connection usage 4.83%

I have checked the MTU, and worked through turning off each security service and trying again. Just wondering if there were any easy checks I can do?

Thanks,

Simon.

shiprasahu93

Hello @Simon_Ward,

Welcome to SonicWall community.

There was a reported issue on 6.5.1.1 and 6.5.2.1 where the downloads were interrupted and the packets were being dropped with the reason 'Drop Code: 139(IDP detection OOO Out of Buffers)'.

If you are seeing something similar in the packet capture while performing the download, kindly upgrade to the latest firmware 6.5.4.7-83n and that should take care of this issue.

https://www.sonicwall.com/support/knowledge-base/how-can-i-setup-and-utilize-the-packet-monitor-feature-for-troubleshooting/170513143911627/

https://www.sonicwall.com/support/knowledge-base/how-can-i-upgrade-sonicos-firmware/170504337655458/

I hope this helps!

Have a good day! Thanks!

Larry

Here's the KB article: https://www.sonicwall.com/support/knowledge-base/how-can-i-troubleshoot-slow-internet-speed-in-sonicwall-firewall-in-two-steps/171025223714035/

Suggest you try changing the DNS servers to either Quad9 (9.9.9.9) or Cloudflare (1.1.1.1) and see if that helps in any way.