ARP configuration

For usage of localports= multipath (see mount parameters, there are several sysctl configuration that need to apply to make sure traffic goes in an out of the correct interface.

rp_filter

When using localports=, make sure that the rp_filter sysctl option is disabled on the corresponding network interfaces, for each interface:

echo 'net.ipv4.conf.<iface>.rp_filter = 0' >> /etc/sysctl.d/nfs-multipath.conf

It may be easier to disable for all of them depending of circumstances:

echo 'net.ipv4.conf.all.rp_filter = 0' >> /etc/sysctl.d/nfs-multipath.conf

To load the new configuration, run /usr/bin/sysctl --system.

arp_announce and arp_ignore

Similar to the above, set, for each interface set:

echo 'net.ipv4.conf.<iface>.arp_announce = 1' >> /etc/sysctl.d/nfs-multipath.conf
echo 'net.ipv4.conf.<iface>.arp_ignore = 2' >> /etc/sysctl.d/nfs-multipath.conf

To load the new configuration, run /usr/bin/sysctl --system.

Persisting sysctl changes with NetworkManager

For setups with NetworkManager, create a script to automatically apply sysctl when interfaces are up:

echo -e '#!/bin/bash\n\n/usr/bin/sysctl --system\n' > /etc/NetworkManager/dispatcher.d/00-sysctl
chmod +x /etc/NetworkManager/dispatcher.d/00-sysctl

Document generated on 2025.11.10 10:07 for v4.5.2~prerelease-1-g37d710094, branch 4.5