Date: Tue, 12 Nov 2024 12:54:04 -0800 From: Patrick Mahan <plmahan@gmail.com> To: freebsd@dreamchaser.org Cc: questions@freebsd.org Subject: Re: missing ARP reply Message-ID: <CAFDHx1LK0LYHhKz8eAN2Hb05VvfexDrccjP--FATNQ4kYZhOzA@mail.gmail.com> In-Reply-To: <76101826-4507-4db4-b7dc-4abb90641713@dreamchaser.org> References: <0f00ea1a-8b62-4c0d-80ee-08721794483b@dreamchaser.org> <76101826-4507-4db4-b7dc-4abb90641713@dreamchaser.org>
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--0000000000008e884e0626bd6b01 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Nov 12, 2024 at 8:35=E2=80=AFAM Gary Aitken <freebsd@dreamchaser.or= g> wrote: > On 11/11/24 21:36, Gary Aitken wrote: > > I'm having trouble with my solar inverter connecting to its home > > base somewhere in Germany and am suspecting a problem with a missing > > ARP reply. > ... > > xxx.yyy is the inverter on the local network xxx.zzz is the fbsd > > gateway/router on the local network > > > > #tcpdump -flnt -i fxp0 | grep 192.168.xxx.yyy ARP, Request who-has > > 192.168.xxx.zzz (aa:bb:cc:dd:ee:ff) tell 192.168.xxx.yyy, length 46 > > IP 192.168.xxx.yyy.3337 > 147.185.237.1.22222: Flags [.], seq > > 26043:26065, ack 708198036, win 2144, length 22 IP > > 147.185.237.1.22222 > 192.168.xxx.yyy.3337: Flags [P.], seq 1:23, ack > > 22, win 18410, length 22 IP 192.168.xxx.yyy.3337 > > > 147.185.237.1.22222: Flags [.], ack 23, win 2144, length 0 > > > > I'm guessing the 3 packets exchanged are a power optimizer reporting > > in, but may be the inverter doing something. > > > > The arp table on xxx.zzz has a permanent entry for itself on the > > interface, picked up from /etc/hosts: > > > > # arp -a ns.dreamchaser.org (192.168.xxx.zzz) at aa:bb:cc:dd:ee:ff on > > fxp0 permanent [ethernet] > > > > Thoughts on why I am not seeing a reply to the ARP request? > > My error; tcpdump does not print the destination host address in the ARP > reply, so grep didn't catch it. duh. Should have been > > tcpdump -flnt -i fxp0 | grep ARP > or > tcpdump -flnt -i fxp0 | grep aa:bb:cc:dd:ee:ff > > Also, tcpdump -e will print the ethernet header of the packet. Also, if you want to watch for only ARP requests then the filter 'arp' will limit the output to only ARP packets, e.g. - tcpdump -i fxp0 -eflnt arp will give you just the ARP traffic. Patrick --0000000000008e884e0626bd6b01 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"ltr"><div dir=3D"ltr">On Tue, Nov 12, 2024 at 8:35=E2=80=AFAM G= ary Aitken <<a href=3D"mailto:freebsd@dreamchaser.org">freebsd@dreamchas= er.org</a>> wrote:</div><div class=3D"gmail_quote"><blockquote class=3D"= gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(20= 4,204,204);padding-left:1ex">On 11/11/24 21:36, Gary Aitken wrote:<br> > I'm having trouble with my solar inverter connecting to its home<b= r> > base somewhere in Germany and am suspecting a problem with a missing<b= r> > ARP reply.<br> ...<br> > xxx.yyy is the inverter on the local network xxx.zzz is the fbsd<br> > gateway/router on the local network<br> > <br> > #tcpdump -flnt -i fxp0 | grep 192.168.xxx.yyy ARP, Request who-has<br> > 192.168.xxx.zzz (aa:bb:cc:dd:ee:ff) tell 192.168.xxx.yyy, length 46 <b= r> > IP 192.168.xxx.yyy.3337 > 147.185.237.1.22222: Flags [.], seq<br> > 26043:26065, ack 708198036, win 2144, length 22 IP<br> > 147.185.237.1.22222 > 192.168.xxx.yyy.3337: Flags [P.], seq 1:23, a= ck<br> > 22, win 18410, length 22 IP 192.168.xxx.yyy.3337 ><br> > 147.185.237.1.22222: Flags [.], ack 23, win 2144, length 0<br> > <br> > I'm guessing the 3 packets exchanged are a power optimizer reporti= ng<br> > in, but may be the inverter doing something.<br> > <br> > The arp table on xxx.zzz has a permanent entry for itself on the<br> > interface, picked up from /etc/hosts:<br> > <br> > # arp -a <a href=3D"http://ns.dreamchaser.org" rel=3D"noreferrer" targ= et=3D"_blank">ns.dreamchaser.org</a> (192.168.xxx.zzz) at aa:bb:cc:dd:ee:ff= on<br> > fxp0 permanent [ethernet]<br> > <br> > Thoughts on why I am not seeing a reply to the ARP request?<br> <br> My error; tcpdump does not print the destination host address in the ARP<br= > reply, so grep didn't catch it.=C2=A0 duh.=C2=A0 Should have been<br> <br> =C2=A0 =C2=A0tcpdump -flnt -i fxp0 | grep ARP<br> or<br> =C2=A0 =C2=A0tcpdump -flnt -i fxp0 | grep aa:bb:cc:dd:ee:ff<br> <br></blockquote><div><br></div><div>Also, tcpdump -e will print the ethern= et header of the packet.=C2=A0 Also, if you want to watch for only ARP requ= ests then the filter 'arp' will limit the output to only ARP packet= s, e.g. - tcpdump -i fxp0 -eflnt arp will give you just the ARP traffic.</d= iv><div><br></div><div>Patrick=C2=A0</div><div><br></div></div></div> --0000000000008e884e0626bd6b01--
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