Bug 843

Summary:	nslookup slow to respond
Product:	Busybox	Reporter:	Chris Miller <chris>
Component:	Networking	Assignee:	unassigned
Status:	RESOLVED WORKSFORME
Severity:	enhancement	CC:	bkuhn, busybox-cvs
Priority:	P5
Version:	1.15.x
Target Milestone:	---
Hardware:	PC
OS:	Windows
Host:		Target:
Build:	v1.11.2

Description Chris Miller 2010-01-07 11:57:48 UTC

nslookup takes a long time to respond with answers under some circumstances.
Looking at a tcpdump, it seems that this is when (for example) a broadband router acting as a DNS proxy, merely forwards the query response as from the real, external DNS server as opposed to from itself.
Busybox/nslookup ignores the response from the external server and repeats the request.
By contrast, requests made to the busybox as a proxy itself seem to be answered almost immediately.
See the attached .cap file for details

Comment 1 万新明 2011-10-18 04:51:54 UTC

I also have this problem. In the networking/nslookup.c file, find the revhost = xmalloc_sockaddr2hostonly_noport (cur-> ai_addr);
Comment it, recompile, re-use nslookup, much faster.

Comment 2 Mike Frysinger 2014-08-10 03:55:42 UTC

pretty sure you're describing C library behavior, not busybox.  busybox merely uses the resolver as configured by the system (e.g. /etc/resolv.conf).