[ Re: Weirdness with ARP on an IBM HS20 blade]

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[ Re: Weirdness with ARP on an IBM HS20 blade]

Sean Dogar
> How about an ifconfig -a from both systems, clearing the arp cache of
> both hosts and capturing tcpdumps on both ends during an entire
> connection attempt?
>

OK.

Here's the ifconfig -a from the OpenBSD box (IP address 172.16.1.22)

lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33224
         groups: lo
         inet 127.0.0.1 netmask 0xff000000
         inet6 ::1 prefixlen 128
         inet6 fe80::1%lo0 prefixlen 64 scopeid 0x6
bge0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
         lladdr 00:09:6b:ff:03:80
         media: Ethernet autoselect (1000baseSX full-duplex)
         status: no carrier
bge1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
         lladdr 00:09:6b:ff:03:81
         groups: egress
         media: Ethernet autoselect (1000baseSX full-duplex)
         status: active
         inet 172.16.1.22 netmask 0xffffff00 broadcast 172.16.1.255
         inet6 fe80::209:6bff:feff:381%bge1 prefixlen 64 scopeid 0x2
pflog0: flags=0<> mtu 33224
pfsync0: flags=0<> mtu 1348
enc0: flags=0<> mtu 1536


Here's the ifconfig -a from another box on the local network (a Linux box)


eth0      Link encap:Ethernet  HWaddr 00:09:6B:B5:25:C0
           inet addr:172.16.1.144  Bcast:172.16.1.255  Mask:255.255.255.0
           inet6 addr: fe80::209:6bff:feb5:25c0/64 Scope:Link
           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
           RX packets:74396848 errors:0 dropped:0 overruns:0 frame:0
           TX packets:124988430 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:169643814 (161.7 MiB)  TX bytes:305112539 (290.9 MiB)
           Interrupt:193

eth1      Link encap:Ethernet  HWaddr 00:09:6B:B5:25:C1
           BROADCAST MULTICAST  MTU:1500  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:1000
           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
           Interrupt:201

lo        Link encap:Local Loopback
           inet addr:127.0.0.1  Mask:255.0.0.0
           inet6 addr: ::1/128 Scope:Host
           UP LOOPBACK RUNNING  MTU:16436  Metric:1
           RX packets:991728 errors:0 dropped:0 overruns:0 frame:0
           TX packets:991728 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:157384504 (150.0 MiB)  TX bytes:157384504 (150.0 MiB)

sit0      Link encap:IPv6-in-IPv4
           NOARP  MTU:1480  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)


The default route for both machines is 172.16.1.1, which corresponds to
a Layer 3 part of a Cisco Catalyst 6506.

I'll clear out the arp caches and work on the tcpdump and submit that in
a bit.  Both of these machines are remote, though, and the tcpdump will
also show a lot of traffic going to and from the machine I'm ssh'ing
into them from, yes?

-Sean

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Re: [ Re: Weirdness with ARP on an IBM HS20 blade]

Melameth, Daniel D.
Sean Dogar wrote:
> > How about an ifconfig -a from both systems, clearing the arp cache
> > of both hosts and capturing tcpdumps on both ends during an entire
> > connection attempt?

> OK.
>
> Here's the ifconfig -a from the OpenBSD box (IP address 172.16.1.22)
>
> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33224
>          groups: lo
>          inet 127.0.0.1 netmask 0xff000000
>          inet6 ::1 prefixlen 128
>          inet6 fe80::1%lo0 prefixlen 64 scopeid 0x6
> bge0: flags=8802<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
>          lladdr 00:09:6b:ff:03:80
>          media: Ethernet autoselect (1000baseSX full-duplex)
>          status: no carrier
> bge1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
>          lladdr 00:09:6b:ff:03:81
>          groups: egress
>          media: Ethernet autoselect (1000baseSX full-duplex)
>          status: active
>          inet 172.16.1.22 netmask 0xffffff00 broadcast 172.16.1.255
>          inet6 fe80::209:6bff:feff:381%bge1 prefixlen 64 scopeid 0x2
> pflog0: flags=0<> mtu 33224
> pfsync0: flags=0<> mtu 1348
> enc0: flags=0<> mtu 1536
>
>
> Here's the ifconfig -a from another box on the local network (a Linux
> box)
>
>
> eth0      Link encap:Ethernet  HWaddr 00:09:6B:B5:25:C0
>            inet addr:172.16.1.144  Bcast:172.16.1.255
>            Mask:255.255.255.0 inet6 addr: fe80::209:6bff:feb5:25c0/64
>            Scope:Link UP BROADCAST RUNNING MULTICAST  MTU:1500
>            Metric:1 RX packets:74396848 errors:0 dropped:0 overruns:0
>            frame:0 TX packets:124988430 errors:0 dropped:0 overruns:0
>            carrier:0 collisions:0 txqueuelen:1000
>            RX bytes:169643814 (161.7 MiB)  TX bytes:305112539 (290.9
>            MiB) Interrupt:193
>
> eth1      Link encap:Ethernet  HWaddr 00:09:6B:B5:25:C1
>            BROADCAST MULTICAST  MTU:1500  Metric:1
>            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:1000
>            RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
>            Interrupt:201
>
> lo        Link encap:Local Loopback
>            inet addr:127.0.0.1  Mask:255.0.0.0
>            inet6 addr: ::1/128 Scope:Host
>            UP LOOPBACK RUNNING  MTU:16436  Metric:1
>            RX packets:991728 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:991728 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:157384504 (150.0 MiB)  TX bytes:157384504 (150.0
> MiB)
>
> sit0      Link encap:IPv6-in-IPv4
>            NOARP  MTU:1480  Metric:1
>            RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>            TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>            collisions:0 txqueuelen:0
>            RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
>
>
> The default route for both machines is 172.16.1.1, which corresponds
> to a Layer 3 part of a Cisco Catalyst 6506.

They both appear to be on the same subnet, so there should be no use of
this gateway.

> I'll clear out the arp caches and work on the tcpdump and submit that
> in a bit.  Both of these machines are remote, though, and the tcpdump
> will also show a lot of traffic going to and from the machine I'm
> ssh'ing into them from, yes?

Yea, but you can also exclude this host from the dump with the
appropriate syntax--maybe someone else knows a better way.

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Re: [ Re: Weirdness with ARP on an IBM HS20 blade]

Sean Dogar
>>The default route for both machines is 172.16.1.1, which corresponds
>>to a Layer 3 part of a Cisco Catalyst 6506.
>
>
> They both appear to be on the same subnet, so there should be no use of
> this gateway.
>

Agreed.  Just wanted to mention it so the mental picture of the network
was clear.


>
>>I'll clear out the arp caches and work on the tcpdump and submit that
>>in a bit.  Both of these machines are remote, though, and the tcpdump
>>will also show a lot of traffic going to and from the machine I'm
>>ssh'ing into them from, yes?
>
>
> Yea, but you can also exclude this host from the dump with the
> appropriate syntax--maybe someone else knows a better way.
>

Thanks for that suggestion.

-Sean