Some Vercel IP addresses are not responding (ISP Viettel)

Hi,

Some domains like `my.nextdns.io` and `ping.nextdns.io` use CNAME records that point to Vercel's servers. Recently, the ISP Viettel I'm using has been having some problems connecting to some Vercel IP addresses. This makes users (at Viettel ISP) unable to access the management page or ping of NextDNS.

I get 2 IP addresses `66.33.60.34` and `66.33.60.194`, then I ping them.

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;my.nextdns.io.                 IN      A
;; ANSWER SECTION:
my.nextdns.io.          300     IN      CNAME   cname.vercel-dns.com.
cname.vercel-dns.com.   1800    IN      A       66.33.60.34
cname.vercel-dns.com.   1800    IN      A       66.33.60.194
;; Query time: 89 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Mon Feb 24 10:46:33 SE Asia Standard Time 2025
;; MSG SIZE  rcvd: 108

Pinging 66.33.60.34 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 66.33.60.34:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Pinging 66.33.60.194 with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for 66.33.60.194:
    Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

Next, I cleared the DNS cache and started over with two other IP addresses in the record, `66.33.60.193` and `66.33.60.130`. It seems that the address `66.33.60.193` is a server in Vietnam (?!)

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;my.nextdns.io.                 IN      A
;; ANSWER SECTION:
my.nextdns.io.          300     IN      CNAME   cname.vercel-dns.com.
cname.vercel-dns.com.   1800    IN      A       66.33.60.193
cname.vercel-dns.com.   1800    IN      A       66.33.60.130
;; Query time: 61 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Mon Feb 24 10:11:47 SE Asia Standard Time 2025
;; MSG SIZE  rcvd: 108

Pinging 66.33.60.193 with 32 bytes of data:
Reply from 66.33.60.193: bytes=32 time=7ms TTL=247
Reply from 66.33.60.193: bytes=32 time=7ms TTL=247
Reply from 66.33.60.193: bytes=32 time=7ms TTL=247
Reply from 66.33.60.193: bytes=32 time=7ms TTL=247
Ping statistics for 66.33.60.193:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 7ms, Maximum = 7ms, Average = 7ms

Pinging 66.33.60.130 with 32 bytes of data:
Reply from 27.68.229.245: TTL expired in transit.
Reply from 27.68.229.245: TTL expired in transit.
Reply from 27.68.229.245: TTL expired in transit.
Reply from 27.68.229.245: TTL expired in transit.
Ping statistics for 66.33.60.130:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Doing the same again, I got 2 IP addresses, one of which already had a ping address.

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;my.nextdns.io.                 IN      A
;; ANSWER SECTION:
my.nextdns.io.          300     IN      CNAME   cname.vercel-dns.com.
cname.vercel-dns.com.   1800    IN      A       76.76.21.164
cname.vercel-dns.com.   1800    IN      A       66.33.60.34
;; Query time: 53 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Mon Feb 24 09:44:04 SE Asia Standard Time 2025
;; MSG SIZE  rcvd: 108

Pinging 76.76.21.164 with 32 bytes of data:
Reply from 76.76.21.164: bytes=32 time=24ms TTL=248
Reply from 76.76.21.164: bytes=32 time=24ms TTL=248
Reply from 76.76.21.164: bytes=32 time=24ms TTL=248
Reply from 76.76.21.164: bytes=32 time=24ms TTL=248
Ping statistics for 76.76.21.164:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 24ms, Maximum = 24ms, Average = 24ms

If this is a Vercel issue, please check it out! Thanks!