DNS resolving

Spider · Post by **Spider** » Thu Sep 23, 2004 5:57 am

Why UnrealIRCd try detect client IP by detected client host name?
I understand if server try to detect client HOST by IP, but why server try to detect client IP by detected HOST?

My DNS have only reverse zone and no forward zone like that:

Code: Select all

#nslookup
Default Server:  ns.kotlowan.pcworld.net
Address:  192.168.0.98

> 192.168.0.21
Server:  ns.kotlowan.pcworld.net
Address:  192.168.0.98

Name:    spider.kotlowan.pcworld.net
Address:  192.168.0.21

> spider.kotlowan.pcworld.net
Server:  ns.kotlowan.pcworld.net
Address:  192.168.0.98

*** ns.kotlowan.pcworld.net can't find spider.kotlowan.pcworld.net: Non-existent domain
>

In result when some one client connected to server ircd don't resolv him host.

[10:16] Alexey ([email protected]) join to channel

can I repair this problem without creating zone?

HELP me please!!!!

AngryWolf · Post by **AngryWolf** » Thu Sep 23, 2004 9:11 am

The IP<->DNS two-way resolution is absolutely necessary because of security. If Unreal didn't do this check, with a trickily configured DNS server and an illegal action, you could have innocent users banned from a channel or a server, in addition, you could even evade certain hostname based bans. These are only a few examples, there must be more.