Forum Discussion

Nimbostratus

Jun 28, 2023

Unable to download 15 MB excel file through LTM.

We have configured HTTP application with port 80 on F5 LTM. We trying to download excel file using that application downloading gets failed after few minutes. No logs found in var/ltm realated to do...

application delivery

Mohamed_Ahmed_Kansoh
Jun 28, 2023
Hi Militza ,

Do you see in Packet captures >>> ( TCP Window Full & TCP zero window ) while downloading this file ?

>Btw , Try to remove the HTTP Profile and use ( Performance layer 4 ) and Test.

>Are there any firewalls between F5 Bigip and Servers or between F5 Bigip and Client ).

> Maybe adjusting window scalling solve your issue , but first tell us if you see ( TCP Window Full & TCP zero window ) flags or not in your captures ?

Militza

Nimbostratus

Jun 28, 2023

Yes performed TCPDUMP and found mutliple tcp retransmited in between F5 and server.

Application is working fine only issue with download file and able to downlad file if access application without F5.

ltm virtual file_download_80 {
creation-time 2022-12-23:12:05:06
destination 10.100.10.11:http
ip-protocol tcp
last-modified-time 2022-12-23:13:33:21
mask 255.255.255.255
persist {
file_download.app/file_cookie-persistence {
default yes
}
}
pool file_download_pool_80
profiles {
file_download.app/file_download_http { }
tcp { }
}
serverssl-use-sni disabled
source 0.0.0.0/0
source-address-translation {
type automap
}
translate-address enabled
translate-port enabled
vs-index 63
}

whisperer
MVP
Jun 28, 2023
Can you also provide the config for the file_download.app/file_download_http object? Usually issues like these result from the HTTP profile.... can you try to remove this profile and re-attempt download to test?
- Militza
  Nimbostratus
  Jun 28, 2023
  ltm profile http file_download.app/file_download_http {
  app-service /Common/file_download.app/file_download_http
  defaults-from http
  insert-xforwarded-for enabled
  redirect-rewrite none
  }