X-Git-Url: https://ruderich.org/simon/gitweb/?a=blobdiff_plain;f=ssh_config;h=3cb065fcb14ae6808fdad3ed4219555d0dcf0214;hb=75e0616f82cd0b9e057692c065ada56de2b4f321;hp=9dc5150803fdb0c04ed89778233d7b85d5c4e218;hpb=84d4c17e1e81a81a9ff8194227d41a8031f9a368;p=config%2Fdotfiles.git

diff --git a/ssh_config b/ssh_config
index 9dc5150..3cb065f 100644
--- a/ssh_config
+++ b/ssh_config
@@ -1,6 +1,9 @@
 # SSH configuration file.
+#
+# Some options are set even if they are default to prevent /etc/ssh/ssh_config
+# from overwriting them.
 
-# Copyright (C) 2011-2012  Simon Ruderich
+# Copyright (C) 2011-2013  Simon Ruderich
 #
 # This file is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -15,31 +18,70 @@
 # You should have received a copy of the GNU General Public License
 # along with this file.  If not, see <http://www.gnu.org/licenses/>.
 
+# Undocumented (and not very well tested) feature. This drops the connection
+# after 5 seconds of inactivity. Thanks to shad0VV in #openssh on Freenode
+# (2012-11-04 18:40 CET) for telling me about this undocumented feature.
+#
+#     ServerAliveCountMax 0
+#     ServerAliveInterval 5
+
 
 # Rules for all hosts.
 Host *
 
-# Force protocol version 2 which is more secure.
+# Force protocol version 2 which is more secure (default).
     Protocol 2
 
-# Disable X11 and agent forwarding for security reasons.
+# Disable X11 and agent forwarding for security reasons (defaults).
     ForwardX11 no
     ForwardAgent no
 # Don't trust remote X11 clients. If enabled allows bad admins complete access
 # to local X11!
     ForwardX11Trusted no
 
-# If -M is used store the control master socket in ~/.ssh. Necessary for
-# ControlMaster to work.
-    ControlPath ~/.ssh/master-%l-%h-%p-%r
+# Disable authentication methods I don't use.
+    ChallengeResponseAuthentication no
+    GSSAPIAuthentication no
+    HostbasedAuthentication no
+    KbdInteractiveAuthentication no
+# Only enable those I need.
+    PasswordAuthentication yes
+    PubkeyAuthentication yes
+
+# Use only authentication identity files configured in ~/.ssh/config even if
+# ssh-agent offers more identities.
+    IdentitiesOnly yes
 
+# Bind local forwardings to loopback only. This way no remote hosts can access
+# them (default).
+    GatewayPorts no
 # Abort if not all requested port forwardings can be set up.
     ExitOnForwardFailure yes
 
-# Don't send any environment variables.
+# Allow using -M (ControlMaster) to create a master SSH session which
+# "tunnels" other connections to the same host, thus reducing the number of
+# authentications (which are relatively slow) and TCP connections. The master
+# sockets are stored in ~/.ssh (by default ControlPath is not set).
+    ControlPath ~/.ssh/master-%l-%h-%p-%r
+# Automatically create a new master session if there's none yet or use an
+# existing one. This way the user doesn't have to use -M to enable a master
+# manually. Don't set this option to "yes" or all SSH commands try to become
+# the master session which is obviously not possible.
+    ControlMaster auto
+
+# Hash hosts in ~/.ssh/known_hosts to try to conceal the known hosts. Doesn't
+# help if the ssh hosts are stored in the shell's history file or in this file
+# as shortcut.
+    HashKnownHosts yes
+
+# Don't permit running local commands (default).
+    PermitLocalCommand no
+
+# Don't send any environment variables (default).
     SendEnv
 
-# Check host IP in known_hosts when connecting to detect DNS spoofing.
+# Check host IP in known_hosts when connecting to detect DNS spoofing
+# (default).
     CheckHostIP yes
-# Ask before adding any host keys to ~/.ssh/known_hosts.
+# Ask before adding any host keys to ~/.ssh/known_hosts (default).
     StrictHostKeyChecking ask