In Robinson's poem, "Mr. Flood's Party," what is the meaning of lines 23 and 24 and of "salutation"?

The poem "Mr. Flood's Party" by American poet Edwin
Arlington Robinson, is a sad tale of the closing phase of one man's life. He has lost
many friends over the years since they died before him: "Where friends of other days
...." He goes to a hilltop above the town, under "the harvest moon" of
autumn.

It is a place that he has frequented in the past, a
place of seemingly fond memory, but a place he hasn't visited for a long while: ""Well,
Mr. Flood, we have not met like this / In a long time; ...." While on the hilltop, he
talks to himself, calling himself "Mr. Flood" as though he were a separate person, and
toasts the friends of the past while he sings "For auld lang syne" in tribute to their
memory. It is with this understanding of the poem that you can identify the meaning of
lines 23 and 24:

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A phantom salutation of the dead
Rang
thinly till old Eben's eyes were
dim.

In this context,
"phantom salutation" is the eerie greeting sent him through his memories of the friends
who are no more: the whispers of greeting that “Rang thinly” from long dead friends and
memories of times together. So "salutation" here means greeting.
This understanding is confirmed in the four final sad lines of the
poem:

There
was not much that was ahead of him,
And there was nothing in the town
below—
Where strangers would have shut the many doors
That many
friends had opened long
ago.

Many years ago, friends
had opened the doors of the cottages in the town below the hilltop, now strangers close
the doors to houses where no friend dwells within. There was not much remaining of his
life, in the autumn of it's days, ahead of him and there was nothing of friendship
awaiting him in the sleeping town below.