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HTTP communication issue throught VPN-SSL


Hi Community,


Having trouble with VPN-SSL access on APM, and not able to find the root-cause. Need your help to find it or the way to do debugging. Here the issue:


I try to mount a VPN-SSL from IE 11 to access a centos server over HTTP and SSH ports. I am working on version v11.5.4 HF3 of bigip appliance.


No issue with SSH, it's working perfectly. But for HTTP access (to an apache2 server) i'm facing a communication issue. IE or Firefox can't download completly big files ( > 3ko about) like images. For a CSS file, a 4.8ko data file, download block every time at 89% for example.


The issue is not visible when i connect the computer directly on LAN. And it's not reproducible for a similar HTTP site hosted on windows IIS server, but reproducible for another web site hosted on a CentOs Apache2 server.


Searching for issue of TCP segmentation or MTU size limit, but regarding the tcdump trace taking from F5 all seems ok. Data are received by the client, a 200 OK HTTP response is acknokedge at the end for the CSS file for example. Nevertheless the file can't be fully downloaded.


To finish, i just found a solution that working perfeclty: Activate the optimization functionnality for my centos host server on Network Access ressource. 0691T000006ApjmQAC.png


An idea of the issue i am facing? And why the optimization functionnality resolv it?


Thanks in advance for your help.