Am 2019-07-11 13:39, schrieb Don Slice:
Any chance you have a default route pointing to a local interface, or have an invalid onlink route making it think destinations are local when they're not? What does you config and routing table look like? Are all the extraneous arps pointing out the same interface?
Thanks a lot, Don! Your first thought was the perfect match. The machines indeed had (for whatever historical reasons) a static route pointed onto themselves. After removing it, the switch CPU load dropped massively (from about 85% to less then 40%). I assume the blackhole never was hit by traffic that was meant to be sent there? Now: funny_hostname# sh ip route a.b.c.d Routing entry for 0.0.0.0/0 Known via "ospf", distance 110, metric 190, best Last update 00:26:58 ago * n.o.p.q, via bond1.310 Routing entry for 0.0.0.0/0 Known via "static", distance 240, metric 0 Last update 1d00h53m ago unreachable (blackhole) Best Bernd
On Thu, Jul 11, 2019 at 3:54 AM Bernd <bernd@kroenchenstadt.de> wrote:
Hi list,
I have a bunch of three routers running in a project, let's call them A, B and C. They connect to multiple AS upstream and internally via OSPF and RIPng.
While B is based on an (ancient) Ubuntu 12.04.5 and (also ancient) Quagga (0.99.20.1), A and C run very recent CentOS 7 and FRR 6.0.2.
B performs perfectly, while A and C put massive pressure on some Cisco switches they're connected to (OSPF and RIPng): They're sending about 2k ARP requests per second each.
Looking at the ARP table (``ip nei show'') of A and C, I see about 20k entries, almost all of them in nud "FAIL" (unreachable). Most of them are IPs within the customer's AS (this is VLAN310 in the graphs attached), but some are random public IPv4 addresses.
I did compare all sysctl settings to no avail, they're all set in a sane and safe manner. Every daemon not needed or adding not necessary complexity (like NetworkManager) is disabled and not running on A and C. ARP flux can be ruled out, too.
Any idea what is going on here?
Best
Bernd_______________________________________________ frog mailing list frog@lists.frrouting.org https://lists.frrouting.org/listinfo/frog
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Don Slice Cumulus Networks