xxxxxxxxxx
#
# Listen locally on port 10001 and tunnel it to someserver
# Listen on someserver port 3128 and tunnel it to localhost
#
ExecStart=/bin/ssh -NT \
-o ExitOnForwardFailure=yes \
-o ServerAliveInterval=60 \
-o ServerAliveCountMax=3 \
-L 172.16.12.34:10001:localhost:10001 \
-R3128:127.0.0.1:3128 \
someserver
xxxxxxxxxx
Just dont forget \ at the end of lines with comments. Systemd will cut them and not use in command
ExecStart=/bin/ssh -NT \
-o ExitOnForwardFailure=yes \
-o ServerAliveInterval=60 \
-o ServerAliveCountMax=3 \
# local tunnel for this \
-L 172.16.12.34:10001:localhost:10001 \
# remote tunnel for that \
-R3128:127.0.0.1:3128 \
someserver