I'm trying to follow this guide to setup NAT on my Synology NAS. It worked great for me! I had everything working perfectly. But when I came back the next morning, the NAS had done a system update [DSM 6.2.2-24922]... The scripts were gone and after recreating them I get errors that the NAT kernel modules cannot be loaded.

Trying to isolate the issue with the insmod, I was able to determine which modules are failing, and see that it is because of "unknown symbols." Here's what I see (note that the variables here are defined in the script at the above link):

# for MODULE in ${KERNEL_MODULES_NAT}; do "${BIN_SYNOMODULETOOL}" --insmod "${SERVICE}" ${MODULE} || echo ${MODULE} = $?; done
nf_conntrack.ko = 1
nf_defrag_ipv4.ko = 1
nf_conntrack_ipv4.ko = 1
nf_nat.ko = 1
nf_nat_redirect.ko = 1
nf_nat_ipv4.ko = 1
iptable_nat.ko = 255
xt_nat.ko = 255
nf_nat_masquerade_ipv4.ko = 1
xt_REDIRECT.ko = 255
ipt_MASQUERADE.ko = 255

# dmesg | tail -10
[ 2448.777252] iptable_nat: Unknown symbol ipt_alloc_initial_table (err 0)
[ 2448.784021] iptable_nat: Unknown symbol ipt_do_table (err 0)
[ 2448.789913] iptable_nat: Unknown symbol ipt_unregister_table (err 0)
[ 2448.796544] iptable_nat: Unknown symbol ipt_register_table (err 0)
[ 2448.818608] xt_nat: Unknown symbol xt_unregister_targets (err 0)
[ 2448.824851] xt_nat: Unknown symbol xt_register_targets (err 0)
[ 2448.862765] xt_REDIRECT: Unknown symbol xt_unregister_targets (err 0)
[ 2448.869368] xt_REDIRECT: Unknown symbol xt_register_targets (err 0)
[ 2448.891826] ipt_MASQUERADE: Unknown symbol xt_register_target (err 0)
[ 2448.898429] ipt_MASQUERADE: Unknown symbol xt_unregister_target (err 0)

I'm really not sure how to fix it. Maybe try to downgrade DSM? Maybe update the objects which are failing to load? Any ideas?

  • Not sure if there's a way to tag users, but I believe this user was the one who wrote that guide? – Kevin Rak May 31 at 15:56

In the end I just installed a TinyCore Virtual Machine on the NAS which can handle the NAT. It seems a bit unnecessary, but I guess it's a little more controllable... so it works.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.