Slowness on a new WAN setup with our zywall 110

My_IT_Hurts

Thanks for all the answers.

So for the mtu the tool also recommends a mtu size of 1428 (did the check with mtu set at 1500 on the zywall). 
The opt port gives the same results.
i also tried with our spare zywall, after a reset, and just opening everything (no more firewall, no content filter activated...) i still got issues with pdf, msi, exe...

I captured the traffic on the zywall (lan and wan) when trying to download this pdf (this one always fails) : https://www.hq.nasa.gov/alsj/a17/A17_FlightPlan.pdf
Some pdf work mostly because, the download speed is so big (for me at least...) that the "blockage" doesn't have time to activate (this is the feeling that it gives)
Can i send it via pm to an "official" zyxel account ?

best regards, and thanks

Zyxel_Stanley

Hi @My_IT_Hurts

You can download .cap file to me by private message. 

TLG

I am having this same problem. When I try to use the Dell Command Update app on Dell PCs to download updates, it is super slow and used to work fine. Also when trying to download an .msi file for a Verizon One Talk app for Windows, it is as the original poster described. It starts out fast, and then slows down and stalls. I also have a Zywall USG 110 and I think this started after the most recent firmware update, or possible the one before that.

My_IT_Hurts

Hi
I thought i'd at least post what solved the issue, which was due to packet loss (seen in wireshark on the zywall captures).
After some pm'ing with someone from zywel, sadly no solution could be found. And the results of this was that some https websites wouldn't load, a lot of download would stop due to data corruption (webserver would end the tcp connections).
So the setup was a zyxel 4/5g modem which was first setup in router mode by our provider, which connected directly to our zywall 110.
After some discussions, they agreed to pass it on bridge modem, to let the zywall handle the connection, it didn't change anything.
What ended up working, was to use a old stormshield sn500 that we got for free (abandonned) and just set it up to handle the connection and route the traffic to the zywall (using a tiny /30 mask).

Zero problems now, everything works like before, except the bandwith is awesome. But when the time to update the zywall will come, i think we'll go to another brand.

Zyxel_Stanley

Hi @My_IT_Hurts
Thanks for shared the issue has resolved after connecting a switch between Zywall110 and LTE modem. In your description, the issue occurs on the connection which connect to LTE modem, the others 3 connections to DSL are working as well.
If connected a switch helps in this case, then it is come from physical interoperability and leads connection unstable symptom. According to interoperability issue we will improve it in the future.
Thank you for advising.