diff --git a/doc/manual/installation/env-variables.xml b/doc/manual/installation/env-variables.xml
index fc39cdd9d..1fd6bafee 100644
--- a/doc/manual/installation/env-variables.xml
+++ b/doc/manual/installation/env-variables.xml
@@ -21,4 +21,51 @@ in your <filename>~/.profile</filename> (or similar), like this:</para>
 <screen>
 source <replaceable>prefix</replaceable>/etc/profile.d/nix.sh</screen>
 
-</chapter>
\ No newline at end of file
+<section xml:id="sec-nix-ssl-cert-file">
+
+<title><envar>NIX_SSL_CERT_FILE</envar></title>
+
+<para>If you need to specify a custom certificate bundle to account
+for an HTTPS-intercepting man in the middle proxy, you must specify
+the path to the certificate bundle in the environment variable
+<envar>NIX_SSL_CERT_FILE</envar>.</para>
+
+
+<para>If you don't specify a <envar>NIX_SSL_CERT_FILE</envar>
+manually, Nix will install and use its own certificate
+bundle.</para>
+
+<procedure>
+  <step><para>Set the environment variable and install Nix</para>
+    <screen>
+$ export NIX_SSL_CERT_FILE=/etc/ssl/my-certificate-bundle.crt
+$ curl https://nixos.org/nix/install | sh
+</screen></step>
+
+  <step><para>In the shell profile and rc files (for example,
+  <filename>/etc/bashrc</filename>, <filename>/etc/zshrc</filename>),
+  add the following line:</para>
+<programlisting>
+export NIX_SSL_CERT_FILE=/etc/ssl/my-certificate-bundle.crt
+</programlisting>
+</step>
+</procedure>
+
+<note><para>You must not add the export and then do the install, as
+the Nix installer will detect the presense of Nix configuration, and
+abort.</para></note>
+
+<section>
+<title><envar>NIX_SSL_CERT_FILE</envar> with macOS and the Nix daemon</title>
+
+<para>On macOS you must specify the environment variable for the Nix
+daemon service, then restart it:</para>
+
+<screen>
+$ sudo launchctl setenv NIX_SSL_CERT_FILE /etc/ssl/my-certificate-bundle.crt
+$ sudo launchctl kickstart -k system/org.nixos.nix-daemon
+</screen>
+</section>
+
+</section>
+</chapter>
diff --git a/scripts/install-multi-user.sh b/scripts/install-multi-user.sh
index 5f6542355..b4eec2fe9 100644
--- a/scripts/install-multi-user.sh
+++ b/scripts/install-multi-user.sh
@@ -727,11 +727,17 @@ setup_default_profile() {
     _sudo "to installing a bootstrapping Nix in to the default Profile" \
           HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_NIX"
 
-    _sudo "to installing a bootstrapping SSL certificate just for Nix in to the default Profile" \
-          HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_CACERT"
+    if [ -z "$NIX_SSL_CERT_FILE" ] || ! [ -f "$NIX_SSL_CERT_FILE" ]; then
+        _sudo "to installing a bootstrapping SSL certificate just for Nix in to the default Profile" \
+              HOME="$ROOT_HOME" "$NIX_INSTALLED_NIX/bin/nix-env" -i "$NIX_INSTALLED_CACERT"
+        export NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt
+    fi
 
+    # Have to explicitly pass NIX_SSL_CERT_FILE as part of the sudo call,
+    # otherwise it will be lost in environments where sudo doesn't pass
+    # all the environment variables by default.
     _sudo "to update the default channel in the default profile" \
-          HOME="$ROOT_HOME" NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt "$NIX_INSTALLED_NIX/bin/nix-channel" --update nixpkgs
+          HOME="$ROOT_HOME" NIX_SSL_CERT_FILE="$NIX_SSL_CERT_FILE" "$NIX_INSTALLED_NIX/bin/nix-channel" --update nixpkgs
 }
 
 
diff --git a/scripts/nix-profile-daemon.sh.in b/scripts/nix-profile-daemon.sh.in
index 4632099e3..52070e36a 100644
--- a/scripts/nix-profile-daemon.sh.in
+++ b/scripts/nix-profile-daemon.sh.in
@@ -49,6 +49,23 @@ if test -w $HOME; then
   fi
 fi
 
-export NIX_SSL_CERT_FILE="@localstatedir@/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"
+
+# Set $NIX_SSL_CERT_FILE so that Nixpkgs applications like curl work.
+if [ ! -z "$NIX_SSL_CERT_FILE" ]; then
+    : # Allow users to override the NIX_SSL_CERT_FILE
+elif [ -e /etc/ssl/certs/ca-certificates.crt ]; then # NixOS, Ubuntu, Debian, Gentoo, Arch
+    export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-certificates.crt
+elif [ -e /etc/ssl/ca-bundle.pem ]; then # openSUSE Tumbleweed
+    export NIX_SSL_CERT_FILE=/etc/ssl/ca-bundle.pem
+elif [ -e /etc/ssl/certs/ca-bundle.crt ]; then # Old NixOS
+    export NIX_SSL_CERT_FILE=/etc/ssl/certs/ca-bundle.crt
+elif [ -e /etc/pki/tls/certs/ca-bundle.crt ]; then # Fedora, CentOS
+    export NIX_SSL_CERT_FILE=/etc/pki/tls/certs/ca-bundle.crt
+elif [ -e "$NIX_USER_PROFILE_DIR/etc/ssl/certs/ca-bundle.crt" ]; then # fall back to cacert in the user's Nix profile
+    export NIX_SSL_CERT_FILE=$NIX_USER_PROFILE_DIR/etc/ssl/certs/ca-bundle.crt
+elif [ -e "/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt" ]; then # fall back to cacert in the default Nix profile
+    export NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt
+fi
+
 export NIX_PATH="nixpkgs=@localstatedir@/nix/profiles/per-user/root/channels/nixpkgs:@localstatedir@/nix/profiles/per-user/root/channels"
 export PATH="$HOME/.nix-profile/bin:$HOME/.nix-profile/lib/kde4/libexec:@localstatedir@/nix/profiles/default/bin:@localstatedir@/nix/profiles/default:@localstatedir@/nix/profiles/default/lib/kde4/libexec:$PATH"