ssh/scp through NAT

sshh_functions.sh

# ssh/scp through NAT, as long as $outer has nc
# ssh v5.4+ should allow ssh -oProxyCommand="ssh -W $inner:%p" $outer $*
# hosts could also be defined in .ssh/config:
#     Host foo
#         hostname inner
#         ProxyCommand ssh outer nc -w 1 %h %p
sshh() {
 [ "$1" = "-h" ] && {
  echo "sshh [opts] outer inner [cmd]"
  return
 }
 [ $2 ] || return
 outer=$1
 shift
 ssh -oProxyCommand="ssh $outer nc -w 1 %h %p" $*
}
sscp() {
 [ "$1" = "-h" ] && {
  echo "sscp [opts] outer file inner:[file]"
  return
 }
 [ $3 ] || return
 outer=$1
 shift
 scp -oProxyCommand="ssh $outer nc -w 1 %h %p" $*
}

sshh_script.sh

#!/bin/bash
# ssh/scp through NAT, as long as $outer has nc
# ssh v5.4+ should allow ssh -oProxyCommand="ssh -W $inner:%p" $outer $*
# hosts could also be defined in .ssh/config:
#     Host foo
#         hostname inner
#         ProxyCommand ssh outer nc -w 1 %h %p
case $(basename $0) in
 sshh) [ $2 ] || exit; action=ssh; usage="sshh [opts] outer inner [cmd]";;
 sscp) [ $3 ] || exit; action=scp; usage="sscp [opts] outer file inner:[file]";;
esac
if [ "$1" = "-h" ]; then
 echo $usage
else
 outer=$1
 shift
 echo $action -oProxyCommand="ssh $outer nc -w 1 %h %p" $*
fi