Unable to download 15 MB excel file through LTM.

Hello,

Can you please provide any additional information? for example: virtual server configuration (virtual server type and profiles assigned) also, is the service working fine and only downloading files is failing?

what is the software version you are running? you can check for any BUG that you might be facing, for example:

https://cdn.f5.com/product/bugtracker/ID966785.html

Also, you can start generating a tcpdump and check the output, it will be clear as the service port is 80, you can use the below command to check out what is actually happennig on both client and  server side.

#tcpdump -nnnveti 0.0:nnnp host 51.39.227.242 and port 80 -s0 -S -w /var/log/filename.pcap

replace the above IP with the client's IP, then open it in wireshark.

Thanks,

You will have to provide more information than that for any assistance here 🙂 Have you performed a tcpdump on client and server side? Have you tried to download the file via curl from thr F5? Can you share your virtual server config from bigip.conf?

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
}

Nothing obvious here that could be causing your issues. Although, the multiple re-transmits is a bit telling. Not sure if this is a new setup, or an older F5 BIG-IP installation. Did you also check the speed/duplex negotiation on the swithports and if you see any drops or issues there?

I changed the virtual server type form standard to performance layer 4 and its started working.

Thanks for all input.