There are 3 hosts: internal, middle, external.
Internal have Internet access through restrictive squid proxy. I have also ssh access to middle and from middle to external. External have internet access, middle only to corporate network.
I've tried to tunnel it with
ssh -t -t -v -L9999:localhost:9932 middle ssh -t -D 9932 external
and setup 127.0.0.1:9999 as SOCKS proxy in firefox but I've got blank page in firefox. Am I doing something wrong or it's due to server capabilities e.g no TCP forward enabled?

EDIT: Ok I solved it with tsocks, it's was probably due to problem with only corporation DNS names resolved on local host. Is there a way to setup DNS through proxy chain, to don't need run each app with tsocks ?

firefox has a setting for that in about config

set it to true

network.proxy.socks_remote_dns

For other apps I do not know