GATE-02: the far side of the wall

Task FSN-2299 · Walk 2026-09-10, 13:04-15:40 · Author facilities & physical security, badge 338110-2 · Ref WLN-2214 (Wardline retirement review), check chk-0041

I was asked to find, physically, the thing that monitoring check chk-0041 has been pinging successfully for eleven years and six months. The review says the answers come from about seventeen metres from the poller. The poller is on the second floor of building one, in the operations room. I walked seventeen metres from it and I found a wall.

What the review handed me

check        chk-0041 ("gate-02 icmp")
target       192.0.2.41
samples      5,785,092 ok / 0 fail, 2015-03-02 to date
median rtt   0.42 ms - about 17 m of cable inside a building
inventory    no row.  DNS: none.  DHCP: none.
             terraform: none.  rack diagrams: none.
route        none - the poller itself cannot send a packet that way

The check answers. The host that runs the check cannot address the target. Those two facts arrived in my queue as one task.

The walk

Seventeen metres from the poller, in a straight line through drywall, is the north stairwell door. I walked the floor with a tape and a rangefinder. What is at seventeen metres:

• The door frame of a service gate. The gate itself is gone. The frame is 2009-spec, painted over twice, and the door-closer is still on it, holding nothing.
• Over the frame, conduit running to a badge-reader position on the corridor side. The reader is there, 2009-spec, same paint. I pulled its head: the cable stub inside is cut flush with the conduit mouth. The cut is old and the copper is green. Nothing has fed that reader in years, and the door it governed was bricked up before this estate's asset register begins.
• The stairwell itself: nothing. Every landing has a camera. I requested the hour around 03:17:09 on 2026-09-07, because the access export says the bay light off that minute and I wanted the frames. The footage shows a wall. Walls do not move.

What I filed

I opened work order FSN-2299 to remove the orphan reader and cap the conduit. While standing at the wall I ran a laptop on the operations room's own network, and chk-0041 polled ok at 0.39 ms with my hand on the plaster. The wall is 0.12 m thick. The stairwell is four metres deep. It is not in the wall, and it is not in the stairwell. The work order closed as asset not present. The check is still green.

The thing I cannot file

My rangefinder says 17.4 m to the far wall of the stairwell, through the door glass. The eleven-year minimum round trip for chk-0041 is 0.31 ms. The minimum I could produce from a laptop patched in the same room, to the poller, all afternoon, was 0.11 ms.

0.31 plus 0.11 is 0.42, which is the median. I wrote that down as arithmetic and not as an opinion, because I do not know which two places the numbers travel between, and the register has no column for a distance with no places.

See also stories/eleven-year-check, stories/axfr-from-53, stories/acx-legacy-01.

Source: the pages linked above, read 2026-09-13. Invented.