On 16/01/16(Sat) 18:40, Doug Moss wrote:
> (my apologies for last message - unfamiliar with Yahoo and forcing plain text 
> email)
> 
> Why is a manually entered permanent arp entry being overwritten?

It should not, are you running -current?  If not could you try?

> 
> At my home, I have an ISP from which I have 5 static IPv4 addresses.
> I use these for my home network, a home email server, jabber server for 
> family/friends,
> website related to my academic work, etc, with different domains.
> 
> 
> The ISP service comes into my home via an ethernet cable which I connect to a 
> switch
> (Cisco gigabit)
> 
> Connected to the switch are:
> (A) router to my home network (behind which are desktops, a wireless access 
> point, kids laptops, etc)
>  a low-power, dual NIC OpenBSD amd64 running NAT and unbound (caching)
>  with IP address 70.20.25.26
> (B) the academic website
>  a low-power, OpenBSD 5.7 amd64
>  with IP address 70.20.25.30
> (plus other servers)
> 
> The ISP gateway/router is IP address 70.20.25.1
> 
> On the academic website, I noticed that the arp table
> showed 70.20.25.26 with the MAC of the ISP gateway
> 
> I thought - why should my private traffic from my personal webserver be routed
> through the ISP gateway - why not go directly to my home network on the same 
> switch?
> 
> So on my webserver, I did this:
> # sudo arp -s 70.20.25.26 00:25:90:0A:69:B6 permanent
> 
> Then I checked:
> # arp -an
> Host                                 Ethernet Address   Netif Expire     Flags
> 70.20.25.1                           fa:c0:01:75:98:cd    em0 19m59s 
> 70.20.25.26                          00:25:90:0a:69:b6    em0 permanent 
> 70.20.25.30                          00:25:90:ea:52:9c    em0 permanent  l
> 
> The next day, I found this is the logs:
> Jan 12 08:17:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> 00:25:90:0a:69:b6 on em0
> Jan 12 08:17:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> fa:c0:01:75:98:cd on em0
> Jan 12 08:37:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> 00:25:90:0a:69:b6 on em0
> Jan 12 08:37:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> fa:c0:01:75:98:cd on em0
> Jan 12 08:57:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> 00:25:90:0a:69:b6 on em0
> Jan 12 08:57:54 www /bsd: arp info overwritten for 70.20.25.26 by 
> fa:c0:01:75:98:cd on em0
> (repeated a couple hundred times)
> 
> $ arp -an
> Host                                 Ethernet Address   Netif Expire     Flags
> 70.20.25.1                           fa:c0:01:75:98:cd    em0 19m54s 
> 70.20.25.26                          fa:c0:01:75:98:cd    em0 17m15s 
> 70.20.25.30                          00:25:90:ea:52:9c    em0 permanent  l
> 
> and
> $ traceroute 70.20.25.26
> traceroute to 70.20.25.26 (70.20.25.26), 64 hops max, 40 byte packets
> 1  lo0-100.BSTNMA-VFTTP-308.verizon-gni.net (70.20.25.1)  2.841 ms  0.594 ms  
> 3.724 ms
> 2  static-70-20-25-26.bstnma.fios.verizon.net (70.20.25.26)  3.544 ms  1.255 
> ms  3.593 ms
> 
> Am I understanding this correctly?
> Is the ISP gateway continuing to try to re-direct the arp table on my home 
> router
> to route traffic out to its gateway before coming back to my home network, 
> instead of
> directly from my router to the other server connected to ports on the same 
> switch?
> 
> 
> Have I done something wrong in my configuration?
> 
> Is this (a) expected (b) strange but innocent (c) nefarious, or (d) something 
> else?

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