2 <b><big>Frequently Asked Questions</big></b>
4 <a href="#f1_0" class="normal">1. General Questions</a><br />
5 <a href="#f1_10" class="normal">1.1 What is SILC?</a><br />
6 <a href="#f1_20" class="normal">1.2 When was SILC Project started?</a><br />
7 <a href="#f1_30" class="normal">1.3 Why SILC in the first place?</a><br />
8 <a href="#f1_40" class="normal">1.4 What license covers the SILC release?</a><br />
9 <a href="#f1_50" class="normal">1.5 Why SILC? Why not IRC3?</a><br />
10 <a href="#f1_55" class="normal">1.6 What platforms SILC supports?</a><br />
11 <a href="#f1_60" class="normal">1.7 Where can I find more information?</a><br />
12 <a href="#f1_70" class="normal">1.8 I would like to help out, what can I do?</a>
14 <a href="#f2_0" class="normal">2. Protocol Questions</a><br />
15 <a href="#f2_10" class="normal">2.1 What is the status of SILC protocol in the IETF?</a><br />
16 <a href="#f2_20" class="normal">2.2 How much the SILC protocol is based on IRC?</a><br />
17 <a href="#f2_30" class="normal">2.3 Why use SILC? Why not IRC with SSL?</a><br />
18 <a href="#f2_40" class="normal">2.4 Can I talk from SILC network to IRC network?</a><br />
19 <a href="#f2_45" class="normal">2.5 Does SILC support file transfer?</a><br />
20 <a href="#f2_47" class="normal">2.6 I am behind a firewall, can I use SILC?</a><br />
21 <a href="#f2_50" class="normal">2.7 How secure SILC really is?</a><br />
22 <a href="#f2_60" class="normal">2.8 Does SILC support instant messaging?</a><br />
23 <a href="#f2_70" class="normal">2.9 Why SILC does not have LINKS command like in IRC?</a><br />
24 <a href="#f2_80" class="normal">2.10 Why SILC does not have STATS command like in IRC?</a><br />
25 <a href="#f2_90" class="normal">2.11 I have suggestions to SILC Protocol, what can I do?</a>
27 <a href="#f3_0" class="normal">3. Client Questions</a><br />
28 <a href="#f3_10" class="normal">3.1 Where can I find SILC clients?</a><br />
29 <a href="#f3_20" class="normal">3.2 Can I use SILC with IRC client and vice versa?</a>
31 <a href="#f4_0" class="normal">4. Server Questions</a><br />
32 <a href="#f4_10" class="normal">4.1 Where can I find SILC servers?</a><br />
33 <a href="#f4_20" class="normal">4.2 Can I run own SILC server?</a><br />
34 <a href="#f4_30" class="normal">4.3 What is the difference between SILC server and SILC router?</a><br />
35 <a href="#f4_40" class="normal">4.4 Why server says permission denied to write to a log file?</a><br />
36 <a href="#f4_50" class="normal">4.5 When I connect to to my server, it says "server does not support one of your proposed cipher", what is wrong?</a>
38 <a href="#f5_0" class="normal">5. Toolkit Questions</a><br />
39 <a href="#f5_10" class="normal">5.1 What is SILC Toolkit?</a><br />
40 <a href="#f5_20" class="normal">5.2 Is the SILC Toolkit Reference Manual Available?</a><br />
41 <a href="#f5_30" class="normal">5.3 How do I compile the Toolkit on Unix</a><br />
42 <a href="#f5_40" class="normal">5.4 How do I compile the Toolkit on Win32</a><br />
46 <b>1. General Questions</b><br /> <br />
49 <samp class="blue">Q: What is SILC?</samp><br />
50 A: SILC (Secure Internet Live Conferencing) is a protocol which provides
51 secure conferencing services in the Internet over insecure channel. SILC
52 is IRC like although internally they are very different. Biggest
53 similarity between SILC and IRC is that they both provide conferencing
54 services and that SILC has almost same commands as IRC. Other than that
55 they are nothing alike.
57 Biggest differences are that SILC is secure what IRC is not in any way.
58 The network model is also entirely different compared to IRC.
62 <samp class="blue">Q: When was SILC Project started?</samp><br />
63 A: The SILC development started in 1996 and early 1997. But, for various
64 reasons it suspended many times until it finally got some wind under its
65 wings in 1999. First public release was in summer 2000.
69 <samp class="blue">Q: Why SILC in the first place?</samp><br />
70 A: Simply for fun, nothing more. And actually for need back in the days
71 when it was started. When SILC was first developed there really did not
72 exist anything like this. SILC has been very interesting and educational
77 <samp class="blue">Q: What license covers the SILC release?</samp><br />
78 A: The SILC software developed here at silcnet.org, the SILC Client, the
79 SILC Server and the SILC Toolkit are covered by the GNU General Public
84 <samp class="blue">Q: Why SILC? Why not IRC3?</samp><br />
85 A: Question that is justified no doubt of that. SILC was not started to
86 become a replacement for IRC. SILC was something that didn't exist in 1996
87 or even today except that SILC is now released. However, I did check out
88 the IRC3 project in 1997 when I started coding and planning the SILC protocol.
90 But, IRC3 is problematic. Why? Because it still doesn't exist. The
91 project is almost at the same spot where it was in 1997 when I checked it
92 out. And it was old project back then as well. That's the problem of IRC3
93 project. The same almost happened to SILC as well as I wasn't making real
94 progress over the years. I talked to the original author of IRC, Jarkko
95 Oikarinen, in 1997 and he directed me to the IRC3 project, although he
96 said that IRC3 is a lot of talking and not that much of anything else. I
97 am not trying to put down the IRC3 project but its problem is that no one
98 in the project is able to make a decision what is the best way to go about
99 making the IRC3 and I wasn't going to be part of that. The fact is that
100 if I would've gone to IRC3 project, nor IRC3 or SILC would exist today. I
101 think IRC3 could be something really great if they just would get their
102 act together and start coding the thing.
106 <samp class="blue">Q: What platforms SILC supports?</samp><br />
107 A: The SILC Client is available on various Unix systems and is reported to
108 work under cygwin on Windows. The SILC Server also works on various Unix
109 systems. However, the server has not been tested under cygwin as far as we
110 know. The SILC Toolkit is distributed for all platforms, Unix, Cygwin
115 <samp class="blue">Q: Where can I find more information?</samp><br />
116 A: For more technical information we suggest reading the SILC Protocol
117 specifications. You might also want to take a look at the <a
118 href="?page=docs" class="normal">documentation </a> page on the web page.
122 <samp class="blue">Q: I would like to help out, what can I do?</samp><br />
123 A: You might want to take a look at the <a
124 href="?page=contribute" class="normal">Contributing</a> page and the <a
125 href="?page=todo" class="normal">TODO</a> list. You might also want to join the
126 SILC development mailing list.
129 <a name="f2_0"></a><br />
130 <b>2. Protocol Questions</b><br /> <br />
133 <samp class="blue">Q: What is the status of SILC protocol in the IETF?</samp><br />
134 A: The SILC protocol specifications has been submitted currently as
135 individual submissions. There does not currently exist a working group
136 for this sort of project. Our goal is to fully standardize the SILC and
137 thus submit it as RFC to the <a href="http://www.ietf.org/" class="normal">IETF</a> at a
142 <samp class="blue">Q: How much SILC Protocol is based on IRC?</samp><br />
143 A: SILC is not based on IRC. The client superficially resembles IRC
144 client but everything that happens under the hood is nothing alike IRC.
145 SILC could *never* support IRC because the entire network toppology is
146 different (hopefully more scalable and powerful). So no, SILC protocol
147 (client or server) is not based on IRC. Instead, We've taken good things
148 from IRC and left all the bad things behind and not even tried to burden
149 the SILC with the IRCs problems that will burden IRC and future IRC
150 projects till the end. SILC client resembles IRC client because it is
151 easier for new users to start using SILC when they already know all the
156 <samp class="blue">Q: Why use SILC? Why not IRC with SSL?</samp><br />
157 A: Sure, that is possible, although, does that secure the entire IRC
158 network? And does that increase or decrease the lags and splits in the
159 IRC network? Does that provide user based security where some specific
160 private message are secured? Does that provide security where some
161 specific channel messages are secured? And I know, you can answer yes to
162 some of these questions. But, security is not just about applying
163 encryption to traffic and SILC is not just about `encrypting the
164 traffic`. You cannot make insecure protocol suddenly secure just by
165 encrypting the traffic. SILC is not meant to be IRC replacement. IRC is
166 good for some things, SILC is good for same and some other things.
170 <samp class="blue">Q: Can I talk from SILC network to IRC network?</samp><br />
171 A: Simple answer for this is No. The protocols are not compatible which
172 makes it impossible to directly talk from SILC network to IRC network or
173 vice versa. Developing a gateway between these two networks would
174 technically be possible but from security point of view strongly not
175 recommended. We have no plans for developing such a gateway.
179 <samp class="blue">Q: Does SILC support file transfer?</samp><br />
180 A: Yes. The SILC protocol support SFTP as mandatory file transfer
181 protocol. It provides simple client to client file transfer, but also
182 a possibility for file and directory manipulation. Even though the SFTP
183 is the file transfer protocol the support for file transferring has been
184 done so that practically any file transfer protocol may be used with SILC
189 <samp class="blue">Q: I am behind a firewall, can I use SILC?</samp><br />
190 A: Yes. If your network administrator can open the port 706 (TCP) you can
191 use SILC without problems. You may also compile your SILC client with
192 SOCKS support which will proxy your SILC session through the firewall.
196 <samp class="blue">Q: How secure SILC really is?</samp><br />
197 A: A good question which I don't have an answer for. We have tried to make
198 SILC as secure as possible. However, there is no security protocol or
199 security software that has not been vulnerable to some sort of attacks.
200 SILC is in no means different from this. So, it is suspected that there
201 are security holes in the SILC. These holes just need to be found so
202 that they can be fixed.
204 But to give you some parameters of security SILC uses the most secure
205 crytographic algorithms such as AES(Rijndael), Twofish, Blowfish, RC5,
206 etc. SILC does not have DES or 3DES as DES is insecure and 3DES is just
207 too slow. SILC also uses cryptographically strong random number generator
208 when it needs random numbers. Public key cryptography uses RSA (PKCS #1)
209 and Diffie-Hellman algorithms. Key lengths for ciphers are initially set
210 to 256. For public key algorithms the starting key length is 1024 bits.
212 But the best answer for this question is that SILC is as secure as its
213 weakest link. SILC is open and the protocol is open and in public thus
214 open for security analysis.
216 To give a list of attacks that are ineffective against SILC:
218 - Man-in-the-middle attacks are ineffective if proper public key
219 infrastructure is used. SILC is vulnerable to this attack if the public
220 keys used in the SILC are not verified to be trusted (as any other
221 protocol for that matter).<br />
222 - IP spoofing is ineffective (because of encryption and trusted keys).<br />
223 - Attacks that change the contents of the data or add extra data to the
224 packets are ineffective (because of encryption and integrity checks).<br />
225 - Passive attacks (listenning network traffic) are ineffective (because
226 of encryption). Everything is encrypted including authentication data
227 such as passwords when they are needed.<br />
228 - Any sort of cryptanalytic attacks are tried to make ineffective by
229 using the best cryptographic algorithms out there.
233 <samp class="blue">Q: Does SILC support instant messaing?</samp><br />
234 A: SILC is not an instant message (IM) system, like ICQ and the others.
235 SILC is more IRC like system, "real-time", connection-oriented chat and
236 that kind of stuff. But I guess IRC is too called an Instant Messaging
241 <samp class="blue">Q: Why SILC does not have LINKS command like in
243 A: It was felt that this information as an own command in SILC is not
244 necessary. Moreover, the topology of the network might be undisclosed
245 information even though the servers and routers in the network are still
246 open. We feel that the network topology information, if it is wanted to be
247 public, and the list of accessible servers can be made available in other
248 ways than providing command like LINKS, which shows the active server
253 <samp class="blue">Q: Why SILC does not have STATS command like in
255 A: This too was considered as information that the protocol should not
256 address. We feel that server implementations will need to implement some
257 sort of adminstrative plugin, or module which provides various means of
258 accessing statistical and other information in the server. And, we do
259 consider this implementation issue, not protocol design issue.
263 <samp class="blue">Q: I have suggestions to SILC Protocol,
264 what can I do?</samp><br />
265 A: All suggestions and improvements are of course welcome. You should read
266 the protocol specifications first to check out whether your idea is
267 covered by them already. The best place to make your idea public is the
268 SILC development mailing list.
272 <a name="f3_0"></a><br />
273 <b>3. Client Questions</b><br /> <br />
276 <samp class="blue">Q: Where can I find SILC clients?</samp><br />
277 A: The SILC client is available for free download from the silcnet.org web
278 page. Some people have also mentioned words Java and Perl when talking
279 about SILC clients. Nothing has appeared yet, though.
283 <samp class="blue">Q: Can I use SILC with IRC client and vice versa?</samp><br />
284 A: Generally the answer would be no for both. However, there exist already
285 at least one IRC client that supports SILC, the <a
286 href="http://irssi.org/" class="normal">Irssi client</a>. The current SILC client is
287 actually based on the user interface of the Irssi client. So, yes it is
288 possible to use SILC with some IRC clients and vice versa. But, this
289 does not mean that you can talk from SILC network to IRC network, that is
293 <a name="f4_0"></a><br />
294 <b>4. Server Questions</b><br /> <br />
297 <samp class="blue">Q: Where can I find SILC servers?</samp><br />
298 A: The SILC server is available for free download from the silcnet.org
299 web page. We are not aware of any other SILC server implementations, so far.
303 <samp class="blue">Q: Can I run own SILC server?</samp><br />
304 A: Yes of course. Download the SILC server package, compile and install
305 it. Be sure to check out the installation instructions and the README
306 file. You also should decide whether you want to run SILC server or SILC
311 <samp class="blue">Q: What is the difference between SILC
312 server and SILC router?</samp><br />
313 A: The topology of the SILC network includes SILC routers and the SILC
314 servers (and SILC clients of course). Normal SILC server does not have
315 direct connections with other SILC servers. They connect directly to the
316 SILC router. SILC Routers may have several server connections and they
317 may connect to several SILC routers. The SILC routers are the servers in
318 the network that know everything about everything. The SILC servers know
319 only local information and query global information from the router when
322 If you are running SILC server you want to run it as router only if you
323 want to have server connections in it and are prepared to accept server
324 connections. You also need to get the router connected to some other
325 router to be able to join the SILC network. You may run the server as
326 normal SILC server if you do not want to accept other server connections
327 or cannot run it as router.
331 <samp class="blue">Q: Why server says permission denied to write to a
332 log file?</samp><br />
333 A: The owner of the log files must be same user that the server is run
334 under, by default it is user `nobody'. Just change the permissions and
339 <samp class="blue">Q: When I connect to my server it says "server does
340 not support one of your proposed ciphers", what is wrong?</samp><br />
341 A: Most likely the ciphers and others has not been compiled as SIMs
342 (modules) and they are configured as modules in the silcd.conf. If they
343 are not compiled as modules remove the module paths from the ciphers and
344 hash functions from the silcd.conf, so that the server use the builtin
345 ciphers. Then try connecting to the server again. It is also possible
346 that the client IS proposing some ciphers that your server does not support.
350 <a name="f5_0"></a><br />
351 <b>5. Toolkit Questions</b><br /> <br />
354 <samp class="blue">Q: What is SILC Toolkit?</samp><br />
355 A: SILC Toolkit is a package intended for software developers who would
356 like to develope their own SILC based applications or help in the
357 development of the SILC. The Toolkit includes SILC Protocol Core library,
358 SILC Crypto library, SILC Key Exchange (SKE) library, SILC Math
359 library, SILC Modules (SIM) library, SILC Utility library, SILC Client
360 library and few other libraries.
364 <samp class="blue">Q: Is the SILC Toolkit Reference Manual Available?</samp><br />
365 A: Yes, partially completed reference manual is available in the Toolkit
366 releases as HTML package and they are available from the silcnet.org
367 website as well at the <a href="?page=docs" class="normal">documentation </a> page.
371 <samp class="blue">Q: How do I compile the Toolkit on Unix?</samp><br />
372 A: You should read the INSTALL file from the package and follow its
373 instructions. The compilation on Unix is as simple as compiling any other
374 SILC package. Give, `./configure' command and then `make' command.
378 <samp class="blue">Q: How do I compile the Toolkit on Win32?</samp><br />
379 A: We have prepared instructions to compile the Toolkit on Win32 in the
380 Toolkit package. Please, read the README.WIN32 file from the package for
381 detailed instructions how to compile the Toolkit for Cygwin, MinGW and
382 native Win32 systems. We have also prepared ready MSVC++ Workspace files
383 in the win32/ directory in the package that will compile automatically
projects / silc.git / blob