Notes for myself, setting up gridftp servers with multiple NICs

Basic installation instructions are at https://twiki.grid.iu.edu/bin/view/Documentation/Release3/InstallOSGGridFTP

A problem arises when the server has multiple interfaces with clients only able to reach one interface (eg., an internal and an external interface, with clients both local and remote)
The server replies with a numerical IP address and port for the data connection, and here is where things can go wrong - the IP address corresponds to only one interface, but the client might only be able to reach the other interface.

One work around is to have multiple instances of the globus-gridftp-server running, each configured explicitly to use one interface.

Copying a few existing service and configuration files and modifying them as necessary to separate the two instances (eg, separate log files and configuration files/directories) easily allows multiple instances to be used.

See for example:

/usr/libexec/globus-gridftp-server-ext-start
/usr/lib/systemd/system/globus-gridftp-server-external.service
/etc/gridftp-ext.d/
/etc/gridftp-ext.conf
/etc/gridftp-ext.d/interface_external.conf
/etc/gridftp.d/interface_internal.conf

(The key here is in the interface_*.conf files, which are where the individual interfaces are specified (control_interface, data_interface and ipc_interface).