Strange DNS issue

[lebowski]

I'm running Debian 12 and running into a strange DNS issue. Ping results in temporary failure issues. It won't resolve entries in the /etc/hosts file either.
dig, nslookup, and host commands do resolve and work correctly though. I've verified my resolv.conf and msswitch.conf are configured correctly. I'm at a loss as to what to try next.

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root@pve:~# ping download.proxmox.com
ping: download.proxmox.com: Temporary failure in name resolution

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root@pve:~# tail /etc/resolv.conf
nameserver 1.1.1.1
nameserver 8.8.8.8

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root@pve:~# host download.proxmox.com
download.proxmox.com is an alias for download.cdn.proxmox.com.
download.cdn.proxmox.com is an alias for us.na.cdn.proxmox.com.
us.na.cdn.proxmox.com is an alias for na2.cdn.proxmox.com.
na2.cdn.proxmox.com has address 170.130.165.90
na2.cdn.proxmox.com has IPv6 address 2a0b:7140:8:100::90
root@pve:~#

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root@pve:~# dig download.proxmox.com

; <<>> DiG 9.18.28-1~deb12u2-Debian <<>> download.proxmox.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 53740
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;download.proxmox.com.          IN      A

;; ANSWER SECTION:
download.proxmox.com.   806     IN      CNAME   download.cdn.proxmox.com.
download.cdn.proxmox.com. 60    IN      CNAME   us.na.cdn.proxmox.com.
us.na.cdn.proxmox.com.  60      IN      CNAME   na.cdn.proxmox.com.
na.cdn.proxmox.com.     60      IN      A       66.70.154.82

;; Query time: 66 msec
;; SERVER: 1.1.1.1#53(1.1.1.1) (UDP)
;; WHEN: Fri Oct 18 22:18:49 CDT 2024
;; MSG SIZE  rcvd: 126

root@pve:~#

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root@pve:~# nslookup download.proxmox.com
Server:         1.1.1.1
Address:        1.1.1.1#53

Non-authoritative answer:
download.proxmox.com    canonical name = download.cdn.proxmox.com.
download.cdn.proxmox.com        canonical name = us.na.cdn.proxmox.com.
us.na.cdn.proxmox.com   canonical name = na2.cdn.proxmox.com.
Name:   na2.cdn.proxmox.com
Address: 170.130.165.90
Name:   na2.cdn.proxmox.com
Address: 2a0b:7140:8:100::90

root@pve:~#

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 /etc/nsswitch.conf
#
# Example configuration of GNU Name Service Switch functionality.
# If you have the `glibc-doc-reference' and `info' packages installed, try:
# `info libc "Name Service Switch"' for information about this file.

passwd:         files systemd
group:          files systemd
shadow:         files systemd
gshadow:        files systemd

hosts:          files dns
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis

/etc/hosts

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66.70.154.82 download.proxmox.com
64.50.236.52 ftp.us.debian.org
151.101.130.132 security.debian.org


# The following lines are desirable for IPv6 capable hosts

#::1     ip6-localhost ip6-loopback
#fe00::0 ip6-localnet
#ff00::0 ip6-mcastprefix
#ff02::1 ip6-allnodes
#ff02::2 ip6-allrouters
#ff02::3 ip6-allhosts

[Aki]

Hello,

I'm running Debian 12 and running into a strange DNS issue. Ping results in temporary failure issues. It won't resolve entries in the /etc/hosts file either.
dig, nslookup, and host commands do resolve and work correctly though. I've verified my resolv.conf and msswitch.conf are configured correctly. I'm at a loss as to what to try next.

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root@pve:~# ping download.proxmox.com
ping: download.proxmox.com: Temporary failure in name resolution

You can try analysing with the following commands (the strace command is required):

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$ sudo apt install strace
$ getent hosts download.proxmox.com
$ strace -s 128 -o log.txt getent hosts download.proxmox.com

The strace command will generate the log.txt file that contains the calls to operating systems services involved with their return values.

If you wish, you can report the output of the previous commands and the log.txt file in one of the following ways:

• paste them into the Debian Pastezone service (https://paste.debian.net) and report the URL/link of the paste in a follow-up message

• attaching the logs to a follow-up forum message as a compressed zip or gz file

• paste logs into the body of a follow-up message between code tags (if they fit the size of a forum message)

Hope this helps.