Hi there..
I am on
"Linux 5.10.0-21-amd64 #1 SMP Debian 5.10.162-1 (2023-01-21) x86_64 GNU/Linux"
The host has a bunch of VLAN intefaces. All works well except the arp table is messed-up and I wonder why. All IP's appear to be on all interfaces, example 100.64.0.34:
Code:
# arp -an | grep 100.64.0.34
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1505
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1506
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1501
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1502
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1510
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.500
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.314
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1507
? (100.64.0.34) at b4:0f:3b:fa:ff:90 [ether] on ens161.1509
TCPdump of the ARP seems to be fine (??):
Code:
# tcpdump -i any arp | grep 100.64.0.34
07:09:36.050439 ens161.1502 Out ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 28
07:09:36.050767 ens161.314 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.500 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1510 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1507 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1509 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1501 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1505 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.050767 ens161.1506 B ARP, Request who-has 100.64.0.34 tell 100.64.0.33, length 46
07:09:36.066682 ens161.1502 In ARP, Reply 100.64.0.34 is-at b4:0f:3b:fa:ff:90 (oui Unknown), length 46
Interfaces look like (they are all separated /30's):
Code:
# ifconfig ens161.1502
ens161.1502: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 100.64.0.33 netmask 255.255.255.252 broadcast 100.64.0.35
inet6 fe80::20c:29ff:fe47:718c prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:47:71:8c txqueuelen 1000 (Ethernet)
RX packets 93581560 bytes 12095853206 (11.2 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 63022644 bytes 177126550268 (164.9 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
# ifconfig ens161.1507
ens161.1507: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 100.64.0.13 netmask 255.255.255.252 broadcast 100.64.0.15
inet6 fe80::20c:29ff:fe47:718c prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:47:71:8c txqueuelen 1000 (Ethernet)
RX packets 43986815 bytes 7216935263 (6.7 GiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 38691972 bytes 80984162080 (75.4 GiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
The hosts's connects to a vswitch on ESXi.
Although everything seems working the arp entries break an integration of another script in my case.
Since all interfaces have separate /30's I'd expect to see each IP only on one interface in the arp table.
Any hint welcome!
Martin
