Re: Try again: IP between Pi <--> klh10 TOPS-20

From	David Todd <hdtodd@gmail.com>
Newsgroups	alt.sys.pdp10
Subject	Re: Try again: IP between Pi <--> klh10 TOPS-20
Date	2026-01-03 18:12 -0500
Organization	A noiseless patient Spider
Message-ID	<5a30daff-a5ef-42a8-a9db-2cbd8b23b45d@gmail.com> (permalink)
References	(3 earlier) <87fr8qfsmp.fsf@atr2.ath.cx> <36bf44a9-b22b-4529-8b69-c3b5598f6a04@gmail.com> <87ldih48o8.fsf@atr2.ath.cx> <fc5af379-0925-4d89-b674-ea3da6ab3db1@gmail.com> <871pk6mxd0.fsf@atr2.ath.cx>

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On 1/3/26 12:15 PM, jayjwa wrote:
> No. Gateway would be the br0 address which you have as .62.

Having the br0 address the same as the DEC20 address
was a critical error.  Fixed. br0 is now .60 and the
DEC20 is .62.

The internet.gateways setting was another critical error!
Thanks for seeing and commenting on that. On the DEC20,
they now look like this:

$cat internet.address
IPNI#0,192.168.1.62,PACKET-SIZE:1500,LOGICAL-HOST-MASK:255.255.255.0,DEFAULT,PREFERRED
$cat internet.gateways
PRIME 192.168.1.60
$

I also now explicitly set the br0 MAC address so that it
and the tap don't end up with the same MAC address.  You
had done that in your script, but I hadn't realized it
was necessary.

So networking between the Pi and DEC20 now work!
Network access to the rest of the LAN is still
broken, but this feels like progress.  No longer
using point-to-point to the bridge, so some hope
of getting full connectivity.

If you could take a look at this again, I'd appreciate
it.  It seems like it should be obvious now where the
problem is, but I still don't see it.

I'm still suspicious of the routing through the bridge.
I've tried with and without the `ip route` command for
the bridge, and external networking is broken in both cases.

The best clue may come from my attempts to ping my Mac (.50)
from the Pi (.88 or .89), and ping thinks it's coming from
the bridge (.60).

$ ping hdt
PING hdt-h (192.168.1.50) 56(84) bytes of data.
 From mac20 (192.168.1.60) icmp_seq=1 Destination Host Unreachable

But the Pi can ping itself, on either interface, just fine.



Here's what I've got now.

----------------------------------------------------------------
In the klt20.ini file:

; Set Ethernet address
devdef ni0 564 ni20 dedic=true ifmeth=tap ifc=tap0

----------------------------------------------------------------

The br0 and tap0 commands to set up the bridge and tap
on the Pi side:

Set up the bridge
+ ip link add name br0 type bridge
+ ip link set br0 type bridge stp_state 1
+ ip link set dev br0 address AA:BB:CC:DD:EE:FF
+ ip link set br0 up
+ ip -4 addr add 192.168.1.60/24 broadcast + dev br0
+ ip route add default via 192.168.1.1 proto static src 192.168.1.60 dev br0

Set up tap0
+ ip tuntap add dev tap0 mode tap
+ ip link set dev tap0 master br0
+ ip link set tap0 up

----------------------------------------------------------------

After the DEC20 boots up, the network looks like this:

hdtodd@pi-5:~ $ ./show-ip.bsh
+ ip address show
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
group default qlen 1000
     link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
     inet 127.0.0.1/8 scope host lo
        valid_lft forever preferred_lft forever
     inet6 ::1/128 scope host noprefixroute
        valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state 
UP group default qlen 1000
     link/ether 2c:cf:67:ad:c9:b9 brd ff:ff:ff:ff:ff:ff
     inet 192.168.1.88/24 brd 192.168.1.255 scope global dynamic 
noprefixroute eth0
        valid_lft 80194sec preferred_lft 80194sec
     inet6 fe80::c953:95e9:baf2:6a3a/64 scope link noprefixroute
        valid_lft forever preferred_lft forever
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel 
state UP group default qlen 1000
     link/ether 2c:cf:67:ad:c9:bb brd ff:ff:ff:ff:ff:ff
     inet 192.168.1.89/24 brd 192.168.1.255 scope global dynamic 
noprefixroute wlan0
        valid_lft 80195sec preferred_lft 80195sec
     inet6 fe80::5018:b779:1c7a:15a3/64 scope link noprefixroute
        valid_lft forever preferred_lft forever
8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state 
UP group default qlen 1000
     link/ether aa:bb:cc:dd:ee:ff brd ff:ff:ff:ff:ff:ff
     inet 192.168.1.60/24 brd 192.168.1.255 scope global br0
        valid_lft forever preferred_lft forever
     inet6 fe80::a8bb:ccff:fedd:eeff/64 scope link proto kernel_ll
        valid_lft forever preferred_lft forever
9: tap0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel 
master br0 state UP group default qlen 1000
     link/ether b6:aa:64:54:dc:99 brd ff:ff:ff:ff:ff:ff
     inet6 fe80::b4aa:64ff:fe54:dc99/64 scope link proto kernel_ll
        valid_lft forever preferred_lft forever
+ ip link show dev br0
8: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state 
UP mode DEFAULT group default qlen 1000
     link/ether aa:bb:cc:dd:ee:ff brd ff:ff:ff:ff:ff:ff
+ ip tuntap show
tap0: tap persist
+ ip route show
default via 192.168.1.1 dev br0 proto static src 192.168.1.60
default via 192.168.1.1 dev eth0 proto dhcp src 192.168.1.88 metric 100
default via 192.168.1.1 dev wlan0 proto dhcp src 192.168.1.89 metric 600
192.168.1.0/24 dev br0 proto kernel scope link src 192.168.1.60
192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.88 metric 100
192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.89 metric 
600
hdtodd@pi-5:~ $

------------------------------------------------------------------
The DEC20 CTY log of the boot process now looks pretty clean:

[KNILDR: Loading microcode version 1(172) into Ethernet channel 0]

Filtered IFE table: 5 entries
  0: "lo" (IP 127.0.0.1) (Netmask 255.0.0.0) UP LOOPBACK
  1: "eth0" (IP 192.168.1.88) (Netmask 255.255.255.0) (Extracted Ether 
2c:cf:67:ad:c9:b9) UP
  2: "wlan0" (IP 192.168.1.89) (Netmask 255.255.255.0) (Extracted Ether 
2c:cf:67:ad:c9:bb) UP
  3: "br0" (IP 192.168.1.60) (Netmask 255.255.255.0) (Extracted Ether 
aa:bb:cc:dd:ee:ff) UP
  4: "tap0" (Extracted Ether b6:aa:64:54:dc:99) UP
[dpni20: osn_pfinit: ifmeth=tap]
[dpni20: osn_pfinit_tuntap, line 1828: Entering, osnpf->osnpf_ifnam is tap0]
[dpni20: osn_pfinit_tuntap, line 1829: Entering, ifnam is tap0]
[dpni20: osn_pfinit_tuntap: Opening TAP device /dev/net/tun]
[dpni20: Entered 10-side of tap0 into table:]
Filtered IFE table: 5 entries
  0: "lo" (IP 127.0.0.1) (Netmask 255.0.0.0) UP LOOPBACK
  1: "eth0" (IP 192.168.1.88) (Netmask 255.255.255.0) (Extracted Ether 
2c:cf:67:ad:c9:b9) UP
  2: "wlan0" (IP 192.168.1.89) (Netmask 255.255.255.0) (Extracted Ether 
2c:cf:67:ad:c9:bb) UP
  3: "br0" (IP 192.168.1.60) (Netmask 255.255.255.0) (Extracted Ether 
aa:bb:cc:dd:ee:ff) UP
  4: "tap0" (Extracted Ether f2:b:a4:59:9a:d6) UP
[dpni20: osn_pfinit_tuntap, line 1863: pfopen(/dev/net/tun, ...)]
[dpni20: pfopen, line 1688: entering, osnpf->osnpf_ifnam=tap0]
[dpni20: pfopen, line 1690: entering, ifname = tap0]
[dpni20: pfopen, line 1716: Try opening basename = '/dev/net/tun']
[dpni20: osn_pfinit_tuntap: ifnam requested as tt_ctx.saved_ifnam was tap0]
[dpni20: osn_pfinit_tuntap: attempt to turn on tap0]
[dpni20: osn_pfinit_tuntap, line 1903: after isdigit(), did set tap0]
[dpni20: osn_pfinit_tuntap: completed]
[dpni20: ifc "tap0" => ether f2:b:a4:59:9a:d6]
[dpni20:   VHOST 0.0.0.0]

SYSJOB 7A(88)-4 started at  3-Jan-2026 1740
SJ  0: @LOGIN OPERATOR
SJ  0:  End of LOGIN.CMD.1
SJ  0: @ENABLE
SJ  0: $SYSTEM:STSJ1
  3-Jan-2026 17:40:28 SYSJB1: SYSJB1 started.
SJ  0: $^ESET LOGIN ANY
SJ  0: $OPR
  3-Jan-2026 17:40:28 SYSJB1: Job 0:
  3-Jan-2026 17:40:28 SYSJB1: Job 0:  KLH20-2.0h Panda Distribution, 
PANDA TOPS-20 Monitor 7.1(21733)-4
  3-Jan-2026 17:40:28 SYSJB1: Job 1:
  3-Jan-2026 17:40:28 SYSJB1: Job 1:  KLH20-2.0h Panda Distribution, 
PANDA TOPS-20 Monitor 7.1(21733)-4
  3-Jan-2026 17:40:28 SYSJB1: Job 2:
  3-Jan-2026 17:40:28 SYSJB1: Job 2:  KLH20-2.0h Panda Distribution, 
PANDA TOPS-20 Monitor 7.1(21733)-4
  3-Jan-2026 17:40:28 SYSJB1: Job 3:
  3-Jan-2026 17:40:28 SYSJB1: Job 3:  KLH20-2.0h Panda Distribution, 
PANDA TOPS-20 Monitor 7.1(21733)-4
  3-Jan-2026 17:40:28 SYSJB1: Job 4:
  3-Jan-2026 17:40:28 SYSJB1: Job 4:  KLH20-2.0h Panda Distribution, 
PANDA TOPS-20 Monitor 7.1(21733)-4
  3-Jan-2026 17:40:28 SYSJB1: Job 1: @LOGIN OPERATOR
  3-Jan-2026 17:40:28 SYSJB1: Job 1:  End of LOGIN.CMD.1
  3-Jan-2026 17:40:28 SYSJB1: Job 3: @LOGIN OPERATOR
  3-Jan-2026 17:40:28 SYSJB1: Job 0: @LOGIN OPERATOR
  3-Jan-2026 17:40:28 SYSJB1: Job 2: @LOGIN OPERATOR
  3-Jan-2026 17:40:28 SYSJB1: Job 4: @LOGIN OPERATOR
  3-Jan-2026 17:40:28 SYSJB1: Job 4:  End of LOGIN.CMD.1
  3-Jan-2026 17:40:28 SYSJB1: Job 0:  End of LOGIN.CMD.1
  3-Jan-2026 17:40:28 SYSJB1: Job 1: @ENABLE
  3-Jan-2026 17:40:28 SYSJB1: Job 2:  End of LOGIN.CMD.1
  3-Jan-2026 17:40:28 SYSJB1: Job 3:  End of LOGIN.CMD.1
  3-Jan-2026 17:40:28 SYSJB1: Job 3: @ENABLE
  3-Jan-2026 17:40:28 SYSJB1: Job 4: @ENABLE
  3-Jan-2026 17:40:28 SYSJB1: Job 0: @ENABLE
  3-Jan-2026 17:40:28 SYSJB1: Job 1: $NETSRV
  3-Jan-2026 17:40:28 SYSJB1: Job 2: @ENABLE
  3-Jan-2026 17:40:28 SYSJB1: Job 2: $SMTJFN
  3-Jan-2026 17:40:28 SYSJB1: Job 3: $MMAILR
  3-Jan-2026 17:40:28 SYSJB1: Job 4: $IMAPSV
  3-Jan-2026 17:40:28 SYSJB1: Job 0: $RESOLV

% [Logger  3-Jan-2026 17:40:30 ]: Started at  3-Jan-2026 17:40:28
SJ  0: OPR>TAKE SYSTEM:SYSTEM.CMD
SJ  0:
SJ  0: 17:40:31	--ORION logging disabled by job 1 OPERATOR at terminal 13--
SJ  0:
SJ  0: 17:40:31	--Output display for OPR modified--
SJ  0:
SJ  0: 17:40:31	--Output display for OPR modified--
SJ  0:
SJ  0: 17:40:31	--Output display for OPR modified--
SJ  0:
SJ  0: 17:40:31	--Output display for OPR modified--
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 0  -- Set Accepted --
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 1  -- Set Accepted --
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 0  -- Set Accepted --
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 1  -- Set Accepted --
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 0  -- Startup Scheduled --
SJ  0:
SJ  0: 17:40:31 	Batch-Stream 1  -- Startup Scheduled --

17:40:31 From operator terminal 13 on node TOPS20::
	=>System in operation
SJ  0: OPR>
SJ  0: 17:40:36	--SEND command completed--
SJ  0: OPR>
SJ  0: 17:40:36 	  -- Structure Status Change Detected --
SJ  0: 		Previously mounted structure TOPS20: detected

  KLH20-2.0h Panda Distribution, PANDA TOPS-20 Monitor 7.1(21733)-4
HDT's KL10/TOPS20

@login hdtodd
  Job 8 on TTY5 3-Jan-2026 17:40:50
   Last interactive login 3-Jan-2026 17:35:57
   Last non-interactive login 29-Dec-2025 08:44:20
  End of LOGIN.CMD.8
@ena
  3-Jan-2026 17:45:05 ACJ: Enable capabilities by job 8, user HDTODD, 
program ENABLE, TTY5
$info inter
  Network Todds.Comcast.net host name is pi20
  Network interface type is IPNI, Internet address is 192.168.1.62
  Network interface is up, output is enabled
  Network service is enabled
  Last network interface up transition: 3-Jan-2026 17:40:28
$

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Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2025-12-29 18:31 -0500
  Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-12-30 12:54 -0500
    Re: Try again: IP between Pi <--> klh10 TOPS-20 Rich Alderson <news@alderson.users.panix.com> - 2025-12-30 20:43 -0500
      Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2025-12-31 12:50 -0500
        Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-01 09:59 -0500
          Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-01 11:08 -0500
            Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-01 11:27 -0500
              Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-02 13:04 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-02 17:36 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-01-03 05:37 +0000
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-03 07:09 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-03 08:40 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-03 11:33 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-03 06:59 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 09:07 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 09:20 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 Johnny Billquist <bqt@softjar.se> - 2026-01-04 16:26 +0100
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 10:57 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-01-05 06:38 +0000
            Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-02 07:46 -0500
              Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-02 12:54 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-02 17:05 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 Rich Alderson <news@alderson.users.panix.com> - 2026-01-02 20:32 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-02 22:21 -0500
            Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-02 17:47 -0500
              Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-03 12:15 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-03 16:57 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-03 17:00 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-04 11:21 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-05 17:52 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-05 18:13 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-06 12:53 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-06 18:12 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <HDTodd@gmail.com> - 2026-01-06 18:15 -0500
                MM vs. MS/MX [was Re: Try again: IP between Pi <--> klh10 TOPS-20] Rich Alderson <news@alderson.users.panix.com> - 2026-01-07 18:28 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-03 17:07 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-04 11:28 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 13:52 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-03 18:12 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 scott@slp53.sl.home (Scott Lurndal) - 2026-01-04 00:00 +0000
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 08:48 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 scott@slp53.sl.home (Scott Lurndal) - 2026-01-04 16:00 +0000
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 14:02 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-04 11:56 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 14:21 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 jayjwa <jayjwa@atr2.ath.cx.invalid> - 2026-01-04 16:16 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 16:58 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 14:28 -0500
                Re: Try again: IP between Pi <--> klh10 TOPS-20 scott@slp53.sl.home (Scott Lurndal) - 2026-01-05 15:33 +0000
                Re: Try again: IP between Pi <--> klh10 TOPS-20 Andy Valencia <vandys@vsta.org> - 2026-01-05 15:45 -0800
                Re: Try again: IP between Pi <--> klh10 TOPS-20 David Todd <hdtodd@gmail.com> - 2026-01-04 08:59 -0500

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