Caches may be configured to serve stale (expired) objects, in order to
improve performance. If an origin server wishes caches to strictly
adhere to expiration information, it can attach a Cache-Control:
must-revalidate header to the original response.

Cache-Control: must-revalidate

The Cache-Control: must-revalidate response header tells caches they
cannot serve a stale copy of this object without first revalidating with
the origin server. Caches are still free to serve fresh copies. If the
origin server is unavailable when a cache attempts a must-revalidate
freshness check, the cache must return a 504 Gateway Timeout error.

as follows:

HTTP/1.1 offers several ways to limit the caching of objects, or the
serving of cached objects, to maintain freshness. The no-store and
no-cache headers prevent caches from serving unverified cached objects:

Cache-Control: no-store
Cache-Control: no-cache
Pragma: no-cache

A response that is marked "no-store" forbids a cache from making a copy
of the response. A cache would typically forward a no-store response to
the client, and then delete the object, as would a non-caching proxy
server.

A response that is marked "no-cache" CAN actually be stored in the local
cache storage. It just cannot be served from the cache to the client
without first revalidating the freshness with the origin server. A
better name for this header might be
"do-not-serve-from-cache-without-revalidation".

The Pragma: no-cache header is included in HTTP/1.1 for backward
compatibility with HTTP/1.0+. HTTP 1.1 applications should use
Cache-Control: no-cache, except when dealing with HTTP 1.0 applications,
which understand only Pragma: no-cache. <FOOTNOTE> Pragma: no-cache is
technically valid only for HTTP requests, yet it is widely used as an
extension header for both HTTP requests and responses.</FOOTNOTE>

"No-Store and No-Cache Response Headers"

/<p> should be </p>

These "expandomatic" features come in a two flavors:

NOW READS:
These "expandomatic" features come in two flavors:

an HTTP version tells the server

NOW READS:
an HTTP version which tells the server

Let's talk in more detail about the some of the basic

NOW READS:
Let's talk in more detail about some of the basic

that the server can used to identify the client

NOW READS:
that the server can use to identify the client

uncommon is real deployments

NOW READS:
uncommon in real deployments

The phrase "or even tens or thousands of simultaneous connections"
should be "or even tens of thousands of simultaneous connections".

"that he second"

NOW READS:
"that the second"

when the server is deleted

NOW READS:
when the object on the server is deleted

If-None-March:

NOW READS:
If-None-Match:

Duplicated period "cache.." HAS BEEN CHANGED to "cache."

allows servers to control the how much

NOW READS:
allows servers to control how much

"Symbolic link cycles usually are the result of an accidental mistake by the server administrator, ..."

NOW READS:
"Symbolic link cycles usually are the result of an unintentional error by the server administrator, ..."

"indentifying"

NOW READS:
"identifying"

A robot is making
should be:
A robot that is making

resource could by dynamically
should be:
resource could be dynamically

Each robots record starts with one or more User-Agent lines...
should be:
Each robot's record starts with one or more User-Agent lines...

NOW READS:
www.robotstxt.org

The comma after "But" should be removed

The comma after "But" should be removed (same error as on p247)

"Each matching cookie much include any Domain,..."

NOW READS:
"Each matching cookie must include any Domain,..."

Need a (d) in front of the last box in the figure.

"...documents in an friendly..."

NOW READS:
"...documents in a friendly..."

the digest provided a correct match for the password.

Plaintext P --> Ciphertext C
Ciphertext C --> Plaintext P

2^128 = 262 x 10^36

NOW READS:
2^128 = 340 x 10^36

The second paragraph (pt 6) and third paragraph contain exactly the same information,
very trivially reworded. For clarity, one or the other should be deleted.

does
should be:
do

and how to replicating content across

NOW READS:
and how to replicate content across

"Its"
NOW READS:
"It's"

"unique"

NOW READS:
"uniquely"

likewise, HTTP traffic

NOW READS:
Likewise, HTTP traffic