PortMapper | remap TCP or UDP traffic

Nevermind my firewall was blocking the application. I was able to dynamically add a firewall rule to fix the issue.

Solution:

A) Disable check for rpcbind in init script

A socket is normally writable until the system buffer is full. That is the reason why many simple select multiplexed system only considere the read part and assume that they will be able to write or accept the possibility of being blocked if they are not.

If you want to be super safe and ensure that you will be able to write, you should ignore EVENT_WRITE unless you are ready to write something. But to prevent your code to exhaust the local memory buffer, the relay should stop reading (also ignore EVENT_READ) if the other channel cannot write.

From the docs:

19.3 The BeanBuilder DSL Explained Using Constructor Arguments

Constructor arguments can be defined using parameters to each bean-defining method. Put them after the first argument (the Class):

Here's the best workbook I've found for troubleshooting NFS connections: https://docs.oracle.com/cd/E23824_01/html/821-1454/rfsadmin-215.html

Follow those instructions slowly and carefully and they should turn up the problem. That doc is a good example of a step-by-step troubleshooting where you check all the connectivity prerequisites before checking the actual service you're trying to test.

Here's some additional info that may help:

• Your network sniff output is simple - the server isn't responding to you on the NFS TCP port. I hope the server's IP isn't really 255.255.255.255, since that's a broadcast address and is unlikely to work reliably.

• You may have dropped all the firewalls, but the NFS server has its own permissions control, in the /etc/exports file according to the HowToForge link that you were following. You need to specify ALL the clients, not just a single IP address. You can also use a network range that includes all the clients. "man 5 exports" should tell you more about how to edit this file. Please DON'T put in "*" to match all IP addresses as suggested in the HowToForge link, that is generally a bad idea.

• portmapper might be using the TCP wrappers permissions files - /etc/hosts.deny and /etc/hosts.allow - see "man 5 hosts_access" for the format of these files. look in the syslog files for the IP address of the client to see if there are any messages about that client.

• Even though you think you turned the firewall off, run "iptables -vL" to see if there are any rules you overlooked and whether they have any hits.

• If you have custom MTU settings on any of the machines (for example, on storage-specific LANs people often set up jumbo packets) make sure that there are no mismatches. This is unlikely to happen on a home network.

• Your sniff shows the client is attempting to connect via TCP to the nfs port 2048, it's possible the client is configured for NFSv4 and the server is configured for NFSv3 or lower. You might see this with the rpcinfo command, since it shows the versions of NFS supported by the server.

The servlet API also allows setting the port mapper using the portMapper() method.

In this case you could use the following configuration