I can't get dns resolver not using my search path.

[hohmann22]

#when trying to run this code

#!/usr/bin/python
import dns.resolver

def resolvOrDie(host,timeout=4):
resolver.lifetime = timeout
resolver.timeout = timeout
if isinstance(host,str):
host = dns.name.from_text(host) # if you set resolver.use_search_by_default = True then you need ot coarse into DNS
try:
answers = resolver.resolve(host) #new way
#answers = resolver.query(host) #deprecated, still works
for answer in answers:
print(answer)
except dns.resolver.NoAnswer:
print("DNS query for", host, "timed out")
except dns.resolver.NXDOMAIN:
print("DNS query for", host, "no record ...")

#Finding A record
#result = dns.resolver.resolve('dfks.com', 'A')

#resolver = dns.resolver.Resolver('/etc/resolv.conf',configure=True) # reads /etc/resolv by default, no need
resolver = dns.resolver.Resolver() # global make a resolver class object seemds to be need for timeout and try

print(f"this is search path {resolver.search}")

#resolver.use_search_by_default = False
resolver.use_search_by_default = True
print("calling with google")
resolvOrDie("google.com")
print ("calling with just fkdsj")
resolvOrDie("fkdsj.com")
resolvOrDie("ansible")
resolvOrDie("hits"
print(resolver.search)

I get this output:

this is search path [, , , , , , ]
calling with google
142.250.191.142
calling with just fkdsj
DNS query for fkdsj.com. timed out
DNS query for ansible. no record ...
DNS query for hits. no record ...
[, , , , , , ]

and I use nslookup
$nslookup ansible | grep -A 2 Name
Name: ansible.umnet.umich.edu
Address: 141.213.135.94

$ nslookup hits | grep -A 2 Name
Name: hits.med.umich.edu
Address: 13.58.255.33

nslookup knows to use my dns search path and resolves. How can I make python do the same thing? I can't seem to figure out how to make dnspython use my search path. What am I missing?

Please let me know if you need any more information

[rthalley]

The problem is this line in resolvOrDie():

host = dns.name.from_text(host)

Dnspython supports both relative and absolute (also known as "fully-qualified") names. By default, dns.name.from_text() will create an absolute name, which you can see is happening in your case looking at your test output:

DNS query for ansible. no record ...

That "." at the end of "ansible." means the name is absolute. Search lists are only applied to relative names. So, one fix is to change that line to

host = dns.name.from_text(host, None)

which will make "www" relative.

But there is a much simpler way to do what you want to do, with searching and a lifetime, and you can even use the default resolver. Just pass a string as the query name, and don't end it with a ".".

answer = dns.resolver.resolve("ansible", search=True, lifetime=5.0)

[hohmann22]

Thank you very much.
Originally when I was just passing the string into, using the resolvOrDie() not using host = dns.name.from_text(host) and set resolver.use_search_by_default = True, I would an error about qname's and only using them? I tried to replicate and it does not seem to do that anymore, but thank you very much for your help and quick response.