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Einstein is currently a virtual machine running on Gourd. Go here for information about the old Einstein hardware.

Virtual Hardware

  • Memory: 2 GB
  • Hard Disk: 20 GB
  • Swap Disk: 4 GB
  • Network 1 (eth0): Farm-Bridge
  • Network 2 (eth1): UNH-Bridge
  • SCSI Controller: LSI Logic

Network Settings

  • IP Address farm (eth0):
  • IP Address UNH (eth1):

Software and Services


Einstein uses the standard NPG iptables firewall. It allows ssh, LDAP, imap, smtp, and http connections.


Einstein is our LDAP server. It provides user authentication among other useful services. LDAP configuration is located in /etc/openldap, and the LDAP database is stored in /var/lib/ldap.


Einstein is our Email server. The mail itself is stored in a raid1 volume on Gourd, and Einstein mounts the NFS share to /var/spool/mail.

Einstein should mount the NFS share at boot, but note that since it mounts by hostname you should make sure that DNS is accessible before starting the Einstein VM. Otherwise mail won't be mounted properly when the system boots. If for some reason DNS is unavailable you can manually mount the NFS share in /mail using gourd's IP address directly.


Einstein provides web-based access to e-mail using Squirrelmail. You can access it at [1].

See also: Gourd/Einstein Migration Plan

Upgrade from RHEL5 to Centos7

OK, this has not been fun, and taken way too long.


We have a running Centos7 Einstein2 system.

  • It has Named installed and running as a slave to Jalapeño.
  • Slapd is installed. Still working on it.


Follow the installation instruction from https://www.certdepot.net/rhel7-configure-ldap-directory-service-user-connection/

Noted differences:

  • Install extra schema:
  • for each do: ldapadd -Y EXTERNAL -H ldapi:/// -D "cn=config" -f <file>
  • (Left out misc.schema and RADIUS-LDAPv3.schema )


You need to configure the TLS certificate for the system. To create a new one (see: certs creating) :

 cd /etc/pki/tls/private
 openssl genrsa -out "$DOMAIN".key 2048 && chmod 0600 "$DOMAIN".key
 openssl req -new -sha256 -key "$DOMAIN".key -out "$DOMAIN".csr
 openssl x509 -req -days 3650 -sha256 -in "$DOMAIN".csr -signkey "$DOMAIN".key -out "$DOMAIN".crt
 openssl pkcs8 -topk8 -inform pem -in "$DOMAIN".key -outform pem -nocrypt -out "$DOMAIN".pem
 chmod 640 "$DOMAIN".key "$DOMAIN".pem
 chgrp ldap "$DOMAIN".key "$DOMAIN".pem
 mv "$DOMAIN".crt ../certs/
 cd ../certs
 ln -s ${DOMAIN}.crt `/etc/pki/tls/misc/c_hash ${DOMAIN}.crt | cut -d' ' -f1`  # Set a link to the hash of the cert.

Install Certificate

Edit an ldif file:

dn: cn=config
 changetype: modify
 replace: olcTLSCACertificatePath
 olcTLSCACertificatePath: /etc/pki/tls/certs
 replace: olcTLSCACertificateFile
 olcTLSCACertificateFile: /etc/pki/tls/certs/ca-bundle.crt
 replace: olcTLSCertificateFile
 olcTLSCertificateFile: /etc/pki/tls/certs/einstein.unh.edu.crt
 replace: olcTLSCertificateKeyFile
 olcTLSCertificateKeyFile: /etc/pki/tls/private/einstein.unh.edu.pem

To make a change to the ldap server:

 ldapmodify -Y EXTERNAL -H ldapi:/// -f /etc/openldap/certificate_change_localhost.ldif

Note that the hostname needs to be correct, so you probably need to set it in /etc/hosts i.e. einstein localhost

Test, add -d1 -d2 or -d3 for increased debug output:

  ldapsearch -x -ZZ 
  ldapsearch -x -H ldaps://  

Make sure that the "authconfig" line from Upgrading to Centos 7 is executed and restart sssd

Import Old Database:

  • Dump on old einstein, see /var/lib/ldap/dump.ldif created by /usr/local/bin/ldap_dump.sh
  • Import with ldapadd -x -w 'password' -D cn=root,dc=physics,dc=unh,dc=edu -f /tmp/dump.ldif

Allow access over SSL:

  • edit: /etc/sysconfig/slapd
  • change: SLAPD_URLS="ldapi:/// ldap:/// ldaps:///"
  • There is still the issue that the TLS is for "einstein" while the testing node is not called "einstein"

Setup /etc/openssl/ldap.conf:

  • echo "tls_reqcert allow" >> /etc/nslcd.conf
    • Note that this makes it so that the TLS is not enforced.

Allow passwd to work

This was darn tricky to find out how to do. The issue is properly modifying, or adding olcAccess to the database. The following does the trick. Create a file change_password_access_policy.ldif in /etc/openldap

 dn: olcDatabase={2}hdb,cn=config
 add: olcAccess
 olcAccess: {0}to attrs=userPassword
   by dn="cn=root,dc=physics,dc=unh,dc=edu" write
   by anonymous auth
   by self write
   by * none
 olcAccess: {1}to dn.base=""
   by * read
 olcAccess: {2}to *
   by dn="cn=Manager,dc=tuxfixer,dc=com" write
   by * read

Then enter the info into LDAP:

 ldapmodify -Y EXTERNAL -H ldapi:/// -f /etc/openldap/change_password_access_policy.ldif

The documentation for olcAccess is here Access Control It appears that the entry for olcAccess: {0} gets encrypted. Weird, since I cannot find any documentation on that.

Other Tasks

Move the Mail configuration. See: E-mail

Move the SSH keys from the system.

Move the sudoers file.