ARP table overflow tuning: Difference between revisions
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By default, the maximum number of entries that can store the ARP table is set to 1024. | By default, the maximum number of entries that can store the ARP table is set to 1024. | ||
In case of virtualization configuration with more than 1024 emulated nodes, this limitation | In case of virtualization configuration with more than 1024 emulated nodes '''on the same ethernet network''', this limitation will be reached. | ||
Linux offers the possibility to overcome this limitation using the sysctl interface. | Linux offers the possibility to overcome this limitation using the sysctl interface. | ||
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net.ipv4.neigh.default.gc_thresh1 = 1024 | net.ipv4.neigh.default.gc_thresh1 = 1024 | ||
See <code class="command"> man 7 arp</code> for more info on the meaning to the gc_threshX sysctl. | |||
Revision as of 16:47, 21 April 2006
By default, the maximum number of entries that can store the ARP table is set to 1024. In case of virtualization configuration with more than 1024 emulated nodes on the same ethernet network, this limitation will be reached.
Linux offers the possibility to overcome this limitation using the sysctl interface.
Choose one of the following:
- Using the
proc filesystem
cat 4096 > /proc/sys/net/ipv4/neigh/default/gc_thresh3 cat 2048 > /proc/sys/net/ipv4/neigh/default/gc_thresh3 cat 1024 > /proc/sys/net/ipv4/neigh/default/gc_thresh3
- Using
sysctl
/sbin/sysctl -w net.ipv4.neigh.default.gc_thresh3 = 4096 /sbin/sysctl -w net.ipv4.neigh.default.gc_thresh2 = 2048 /sbin/sysctl -w net.ipv4.neigh.default.gc_thresh1 = 1024
- Setting it up definitively editing the
/etc/sysctl.confconfiguration file and adding:
net.ipv4.neigh.default.gc_thresh3 = 4096 net.ipv4.neigh.default.gc_thresh2 = 2048 net.ipv4.neigh.default.gc_thresh1 = 1024
See man 7 arp for more info on the meaning to the gc_threshX sysctl.