- What server versions can I connect my server to?
2.10.0, 2.10.1 and 2.10.2 are fully compatible with 2.9.x servers.
2.9.x are fully compatible with 2.8.x servers. Be sure to
#undef NoV28Links in the
config.h file
Only versions 2.9.1 and 2.9.2 can be linked on a net
where 2.7.x servers are present.
Only versions 2.9.1, 2.9.2 and 2.9.3 can be directly
linked to a 2.8.x server.
No 2.10.x version can be directly linked to 2.8.x server.
For various reasons it's better to run a homogenous network of latest version.
- What is ND, CD, TS?
ND stands for Nick Delay which is a mechanism to prevent
nickname collisions,
CD stands for Channel Delay which is a mechanism to prevent
channel collisions (op riding),
TS stand for TimeStamp which is a mechanism to solve
nickname and channel collisions by deciding which of the two
concerned parties is right, and which is wrong.
Here are some links to documents that should help you:
2.9.x and 2.10.x are the only versions implementing Nick and Channel Delay.
These two mechanisms have proven to be effective in greatly
reducing the number of channel takeovers, and nickname collisions.
In recent years, however, they seem not enough for prolonged splits
caused by (Distributed) Denial Of Service attacks.
- What is ``flood control''?
This is the name for the feature which prevents the server
to be flooded by clients. It can be tuned via the
CLIENT_FLOOD define. It is
different from the penalty system described below. Both are
complementary.
If a client sends too much data to the server, its
connection will be closed.
- What is ``penalty''?
This feature appeared in 2.9.1 in replacement of some old
less flexible equivalent mechanism. Each command of the
server has a penalty which will be applied to the client
running this command.
The penalty is defined in seconds. If a user's penalty
exceeds 10 seconds, any incoming data is delayed, and only
processed when the penalty goes under 10 seconds again.
Many people would like a list of penalties, unfortunately,
it is quite difficult to make one. The only way to know is
to RTFS.
Most of the time, commands which affect the net
have a high penalty. (For example, doing a remote WHOIS is
more penalized than doing a WHOIS locally).
- What is a service?
Bjørn Borud wrote ``A service is something between a
client and a server connection. if you read the docs
accompanying ircd 2.9.2 you will get some idea as to what it
can be used for given some knowledge of the IRC
protocol.''
2.9.3 is the first version fully supporting
services (which abilities have been slightly enhanced).
Commands that a user can issue:
- SERVLIST <pattern> <type>
This will return a list of matching services.
- SQUERY <pattern> <query>
This will send the string <query> to the first service
found which name matches <pattern>.
Services cannot join channels.
It is also interesting to note that services are not necessarily
seen by the whole IRC network. A service which you cannot see
cannot see you either. Services distribution is controlled by
a mask, for example *.fr would restrict a service to be present
only on french servers.
Here is a small perl script which
behaves as a service.
- What does that character mean in the user log?
This is defined in the common/struct_def.h file (see below) and tells why the client
connection was closed.
#define EXITC_UNDEF '-' /* unregistered client */
#define EXITC_REG '0' /* normal exit */
#define EXITC_DIE 'd' /* server died */
#define EXITC_DEAD 'D' /* socket died */
#define EXITC_ERROR 'E' /* socket error */
#define EXITC_FLOOD 'F' /* client flooding */
#define EXITC_KLINE 'k' /* K-lined */
#define EXITC_KILL 'K' /* KILLed */
#define EXITC_MBUF 'M' /* mem alloc error */
#define EXITC_PING 'P' /* ping timeout */
#define EXITC_SENDQ 'Q' /* send queue exceeded */
#define EXITC_RLINE 'r' /* R-lined */
#define EXITC_REF 'R' /* Refused */
If the character is not above, you have to check your copy of common/struct_def.h
file.
- What are those 4 last numbers in the logs?
2.9.3 extends logging information by providing the amount of
data transferred during the connection between the client
and the server:
- number of messages sent to the client.
- Kbytes sent to the client.
- number of messages received by the server.
- Kbytes received by the server.
- What are all those prefixes used for usernames?
Prefixes used are:
none I line with ident
^ I line with OTHER type ident
~ I line, no ident
+ i line with ident
= i line with OTHER type ident
- i line, no ident
- What do the comments in server kills mean?
See http://www.irc.org/tech_docs/ircnet/kills.html
for a complete description of KILL notices.
Note that the description field of server kills has changed
several times, this document describes the notices which can
be generated by the version 2.9.3 (and further) of the server.
- Is ircd vulnerable to the DNS cache bug?
Yes.
However, it is possible to protect the server from such abuse.
ircd reads the /etc/resolv.conf file to setup its own resolver
and will use the nameservers defined in this file. There are
two ways ircd can be tricked to accept a wrong answer, both can be
defeated if the abusers cannot find the DNS server used by ircd.
The file used by ircd to setup its resolver can be changed at
compile time. The default path (/etc/resolv.conf) is set in
include/resolv.h up to version 2.9.3
The 2.9.4 version introduces the option --resconf to configure
which makes it easy to use an alternate file.
- Can ircd refresh the list of nameservers?
No.
