First of all, thank you for your AsusWrt software. It's been really donation-worthy appreciated
I am in the same boat as nbdwt73. I want to mount an NFS exported path from my NAS on the router (RT-AC5300,firmware 384.11_2) and thus make it available as a read-only folder through the router-based FTP server. This is, in my view, much better than spinning up an FTP server on NAS and then port-forwarding a bunch of ports.
After spending a whole day trying to solve the connection problem that only manifested itself as the error message:
pmap_getmaps rpc problem: RPC: Unable to receive; errno = Connection timed out
mount: RPC: Remote system error - Connection refused
I was stumped. A Linux box mounted that export just fine. "showmount -e" on the router listed the export. I was starting to think that this was connected to incompatibility between portmap on the router and rpcbind on the server.
This thread provided a much-needed break-through. I have disabled the Two-Way IPS and was immediately able to mount the exported path. After this I could re-enable the IPS protection without losing the NFS connection.
It looks like TrendMicro is only blocking the initial handshake, when the NFS server tries to talk back to the client. It does say on the package: "Additionally, Two-Way IPS detects suspicious outgoing packets from infected devices and avoids botnet attacks."
The call to
# rpcinfo -p router_ip
from the NFS server times out with IPS activated, but would show the correct list of service ports with IPS deactivated:
program vers proto port service
100000 2 tcp 111 rpcbind
100000 2 udp 111 rpcbind
100024 1 udp 41420 status
100024 1 tcp 46031 status
100003 3 tcp 2049 nfs
100003 3 udp 2049 nfs
100021 1 udp 39366 nlockmgr
100021 3 udp 39366 nlockmgr
100021 4 udp 39366 nlockmgr
100021 1 tcp 55899 nlockmgr
100021 3 tcp 55899 nlockmgr
100021 4 tcp 55899 nlockmgr
100005 3 udp 57582 mountd
100005 3 tcp 56163 mountd
Luckily the router does not need frequent reboots - 3-4 times per year, so a manual ritual of disabling IPS, SSH-remoting to the router, running "mount" manually and then re-enabling IPS is feasible.
