What is the catch of the SQUID ignore_expect_100 option?

Question

Squid

The transport company rolled out a web service (works over http). When working through SQUID, the program gives an HTTP error 417. This is solved by enabling the option in the SQUID config: ignore_expect_100 on There is a comment on
the page www.squid-cache.org/Doc/config/ignore_expect_100 may not handle it well..
As I understand it, this option is more of a rake, in case the application does not process http headers quite correctly. I found about it on the net: the option allows NOT to send error 417 to clients with HTTP / 1.1 support curve. By default, this option is disabled and squid ignores headers like Expect: 1XX in requests (according to RFC 2616).
Question: What are the negative consequences of enabling this option? The risk of exploiting browser vulnerabilities, for example, or something else unpleasant, increases.

Answer 1

It doesn't threaten anything. It's just a crutch, but like any crutch, it's not very good. Just an option made for compatibility with crooked clients