comparison SMALL @ 4:fe6bca95afa7

Makefile.in contains updated files required
author Matt Johnston <matt@ucc.asn.au>
date Tue, 01 Jun 2004 02:46:09 +0000
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children b9d3f725e00b
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1 Tips for a small system:
2
3 The following are set in options.h
4
5 - You can safely disable blowfish and twofish ciphers, and MD5 hmac, without
6 affecting interoperability
7
8 - If you're compiling statically, you can turn off host lookups
9
10 - You can disable either password or public-key authentication, though note
11 that the IETF draft states that pubkey authentication is required.
12
13 - Similarly with DSS and RSA, you can disable one of these if you know that
14 all clients will be able to support a particular one. The IETF draft
15 states that DSS is required, however you may prefer to use RSA.
16 DON'T disable either of these on systems where you aren't 100% sure about
17 who will be connecting and what clients they will be using.
18
19 - Disabling the MOTD code and SFTP-SERVER may save a small amount of codesize
20
21 - You can disable x11, tcp and agent forwarding as desired. None of these are
22 essential, although agent-forwarding is often useful even on firewall boxes.
23
24 If you are compiling statically, you may want to disable zlib, as it will use
25 a few tens of kB of binary-size (./configure --disable-zlib).
26
27 You can create a combined binary, see the file MULTI, which will put all
28 the functions into one binary, avoiding repeated code.
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30 If you're compiling with gcc, you might want to look at gcc's options for
31 stripping unused code. The relevant vars to set before configure are:
32
33 LDFLAGS=-Wl,--gc-sections
34 CFLAGS="-ffunction-sections -fdata-sections"
35
36 You can also experiment with optimisation flags such as -Os, note that in some
37 cases these flags actually seem to increase size, so experiment before
38 deciding.
39
40 Of course using small C libraries such as uClibc and dietlibc can also help.
41
42 If you have any queries, mail me and I'll see if I can help.