This command shows the kernel modules that are currently loaded.

# lsmod

Module                  Size  Used by
vboxdrv                55088  0
autofs4                20421  2
ipt_MASQUERADE          6721  1
iptable_nat             9669  1
nf_nat                 18669  2 ipt_MASQUERADE,iptable_nat
nf_conntrack_ipv4      11717  2 iptable_nat
nf_conntrack           51977  4 ipt_MASQUERADE,iptable_nat,nf_nat,nf_conntrack_ipv4
....