NFS - Notes

2022-01-29 399 words 2 minutes

Contents

Exports File

Files:

/etc/exports or /etc/exports.d/<name>.exports

File is space separated share host1 host2 or ip1 ip2… or *.domain /path/to/share <hostname.fqd> or <ip_address>

Example:

/myshare host1.example.com

Export options

/myshare server1.example.com(ro) - read only

Options are put in () after the host or ip. There is no space. Some common options: rw, ro,

Apply changes to exports file with cmd:

exportfs -r

NFS Security

NFS has the following security typs:

Type	Description
None	None allows anonymous access to the file share to all hosts specified in the exports file. This options requires the SELinux boolean “nfsd_annon_write” to be enabled
Sys	File access is based on posix permissions. This is the default if not specified
Krb5	Clients provide identity using kerberos and then posix permissions apply
Krb5i	Adds a cryptographically strong guarantee that data in each request has not been tampered with
Krb5p	Adds encryption to all requests between client and server. This is the most security but has a performance impact

NFS services

nsf-server

If using kerberos: nfs-secure-server must also be running and enabled.
Client requires nfs-secure to connect to kerberos export, as well as a /etc/krb5.keytab file

Server config (krb5)

Download keytab

wget -O /etc/krb5.keytab http://address.example.com/keytab

Enable nfs version 4.2 in /etc/sysconfig/nfs - to export SELinux labels

Change RPCNFSDARGS="" to RPCNFSDARGS="-V 4.2"

systemctl enable nfs-secure-server --now

Make exports directory

Add directory to /etc/exports file

Example: /myshare desktop1(sec=krb5p,rw)
Exportfs -r

Open firewall ports

Firewall-cmd --permanent --add-service=nfs
Firewall-cmd --reload

Mount nfs filesystem on client

Download keytab wget -O /etc/krb5.keytab <url>
systemctl start nfs-secure
systemctl enable nfs-secure

Make directory to mount filesystem

Add share to fstab server.fqdn:/path/to/share /path/to/mount nfs defaults,sec=krb5p,v4.2 0 0

Client config

Download keytab systemctl start nfs-secure and enable

Client Fstab

server:/share /mount/point nfs defaults,v4.2,sec=krb5p 0 0

NFS firewall

sudo firewall-cmd --permanent --add-service=nfs

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Thanks!

Luke