diff --git a/lib/modem.js b/lib/modem.js
index cd89dd0..c845911 100644
--- a/lib/modem.js
+++ b/lib/modem.js
@@ -47,6 +47,7 @@ var defaultOpts = function() {
     } else if (host.protocol === 'ssh:') {
       opts.protocol = 'ssh';
       opts.username = host.username;
+      opts.sshAuthAgent = process.env.SSH_AUTH_SOCK;
     } else {
       opts.protocol = 'http';
     }
@@ -84,6 +85,7 @@ var Modem = function(options) {
   this.checkServerIdentity = opts.checkServerIdentity;
   this.agent = opts.agent;
   this.headers = opts.headers || {};
+  this.sshAuthAgent = opts.sshAuthAgent;
 
   if (this.key && this.cert && this.ca) {
     this.protocol = 'https';
@@ -205,7 +207,7 @@ Modem.prototype.buildRequest = function(options, context, data, callback) {
   var connectionTimeoutTimer;
 
   var opts = self.protocol === 'ssh' ? Object.assign(options, {
-    agent: ssh({'host': self.host, 'port': self.port, 'username': self.username, 'agent': process.env.SSH_AUTH_SOCK}),
+    agent: ssh({'host': self.host, 'port': self.port, 'username': self.username, 'agent': self.sshAuthAgent}),
     protocol: 'http:'
   }) : options;