HTTP/2 max header size

Server NGINX
1

Hi,

I was using “nghttp” command line tool to test NGINX. I enabled
“continuation” option in “nghttp” command line tool, which filled the
HEADERS frame with a very large header field/value. Then I got an GOAWAY
frame with error code of “ENHANCE_YOUR_CALM(0x0b)”. Then I checked the
debug log file of the server, and found “client exceeded
http2_max_header_size limit while processing HTTP/2 connection”.

May I know the consideration about this limitation? For a client, it may
not be able to know the precise value of “http2_max_header_size”. Once a
client gets this error, how can it recover from it or request the
resource
successfully?

Thanks!

Shengtuo Hu

2

On Tuesday 26 January 2016 15:14:04 Shengtuo Hu wrote:

not be able to know the precise value of “http2_max_header_size”.
Decompression and processing of headers require proportional amount of
memory.
The consideration is simple: to limit the amount of memory that can be
eaten by
a client and prevent DoS attack on the server.

Once a client gets this error, how can it recover from it or request
the resource successfully?

[…]

If a client gets this error then either it is doing something wrong by
sending
incorrect requests, or the server is configured incorrectly.

wbr, Valentin V. Bartenev