Date: Wed, 26 Nov 2014 07:46:28 +0200 From: Riaan Kruger <riaank@gmail.com> To: freebsd-questions@freebsd.org Subject: Possible CARP routing issue Message-ID: <CABNwDi0LiEueW%2BU9jypPGvtSxYqShSLZZNnpT1b1oRc-f=DTZA@mail.gmail.com>
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It seems that in some circumstances routing is not playing well with CARP. We have the following scenario. Device A --------- 192.168.1.10 Router: ------- 10.0.0.1 Device B -------- Interface 1 Virtual IP (CARP): 172.16.1.3 Interface 1 Real IP: 172.16.1.2 Routing table of device B: 0.0.0.0 10.0.0.1 192.168.1.0 10.0.0.1 etc ... When Device A pings the Real IP of Device B (172.16.1.2) we see the following ARP request packet: ARP request who has 192.168.1.10 tell 172.16.1.3 In other words pinging the real IP causes the Virtual IP to ask for the MAC address of the pinging device, even though they are not in the same subnet and there is a default route. Pinging the virtual IP does not induce this ARP request and the ping is successful. When deleting the second route from the routing table above the ARP request is not sent. I know the second route is superfluous but it is put there by third party software. The real issue is why this behavior happens with CARP. Is it an indication of some underlying problem? Riaan
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