Server not able to reach to DNS server intermittently - Linux

Hello,
I have RHEL 7.6. Its resolv.conf has 4 DNS servers. It takes a very long time when I login with NIS account. To check the server's connectivity, I tried to ping its DNS servers and found that ping stops in between. It is not "time-out", but ping just freezes for 10-20 seconds and then starts pinging and after a while, again same behavior. I compared routes, netmask, and gateway seems to be comparable with other similar servers. selinux is disabled and firewalld is disabled.

Here is ping to one of DNS server :
Code:[root@db-pol45 ~]# cat /etc/resolv.conf
domain xxyyxxyy.com
nameserver 192.168.123.44
nameserver 192.168.123.45
nameserver 192.168.187.44
nameserver 192.168.187.45
search xxyyxxyy.com
[root@db-pol45 ~]# ping 192.168.123.4
64 bytes from 192.168.123.44: icmp_seq=472 ttl=61 time=0.689 ms
64 bytes from 192.168.123.44: icmp_seq=473 ttl=61 time=0.662 ms
64 bytes from 192.168.123.44: icmp_seq=474 ttl=61 time=0.734 ms
64 bytes from 192.168.123.44: icmp_seq=475 ttl=61 time=0.930 ms
64 bytes from 192.168.123.44: icmp_seq=476 ttl=61 time=0.783 ms
64 bytes from 192.168.123.44: icmp_seq=477 ttl=61 time=1.20 ms
64 bytes from 192.168.123.44: icmp_seq=478 ttl=61 time=0.670 ms
64 bytes from 192.168.123.44: icmp_seq=479 ttl=61 time=0.899 ms
64 bytes from 192.168.123.44: icmp_seq=480 ttl=61 time=1.04 ms
64 bytes from 192.168.123.44: icmp_seq=481 ttl=61 time=2.97 ms
64 bytes from 192.168.123.44: icmp_seq=482 ttl=61 time=4.16 ms
64 bytes from 192.168.123.44: icmp_seq=483 ttl=61 time=2.83 ms
64 bytes from 192.168.123.44: icmp_seq=526 ttl=61 time=0.678 ms
64 bytes from 192.168.123.44: icmp_seq=527 ttl=61 time=0.681 msAnd traceroute :
Code:[root@db-pol45 ~]# [root@db-pol45 ~]# traceroute 192.168.123.44
traceroute to 192.168.123.44 (192.168.123.44), 30 hops max, 60 byte packets
1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 * wksx-ins1-prod.xxyyxxyy.com (192.168.123.44) 1.617 ms 1.714 ms
[root@db-pol45 ~]# traceroute 192.168.123.44
traceroute to 192.168.123.44 (192.168.123.44), 30 hops max, 60 byte packets
1 seawa-prod-lb-v67.xxyyxxyy.com (192.168.42.4) 0.176 ms 0.163 ms 0.144 ms
2 seawa-comm-fw1-e2-1.xxyyxxyy.com (216.221.128.65) 0.638 ms 0.748 ms 0.335 ms
3 seawa-emer-fw1.xxyyxxyy.com (192.168.150.213) 1.332 ms 1.515 ms 1.930 ms
4 * wksx-ins1-prod.xxyyxxyy.com (192.168.123.44) 1.629 ms *
[root@db-pol45 ~]# traceroute 192.168.123.44
traceroute to 192.168.123.44 (192.168.123.44), 30 hops max, 60 byte packets
1 seawa-prod-lb-v67.xxyyxxyy.com (192.168.42.4) 0.126 ms 0.092 ms 0.138 ms
2 seawa-comm-fw1-e2-1.xxyyxxyy.com (216.221.128.65) 0.374 ms 0.510 ms 0.615 ms
3 seawa-emer-fw1.xxyyxxyy.com (192.168.150.213) 2.302 ms 2.424 ms 2.256 ms
4 wksx-ins1-prod.xxyyxxyy.com (192.168.123.44) 2.494 ms 2.464 ms 2.278 ms
[root@db-pol45 ~]#All 4 DNS servers are fine. From DNS servers, I can traceroute db-pol45 easy.

I ran "mtr 192.168.123.44" on 4 windows, with a gap of 4-5 seconds. These servers are not open to the internet, so I chose 192.168.123.44 as the internal server.

Not all 4 sessions are showing me frozen at same time. I tried "mtr 192.168.123.22" also, which is also in same VLAN. That also shows me the same behavior. At one time (or probably difference of 1 second, because copy-paste took 1 second), here are 4 outputs :
Code:Host Loss% Snt Last Avg Best Wrst StDev
1. seawa-prod-lb-v67.xxyyxxyy.com 37.3% 201 0.3 0.2 0.1 0.4 0.0
2. seawa-comm-fw1-e2-1.xxyyxxyy.c 37.3% 201 0.5 1.5 0.3 54.5 6.0
3. seawa-emer-fw1.xxyyxxyy.com 37.3% 201 0.6 0.8 0.4 7.1 0.8
4. wksx-ins1-prod.xxyyxxyy.com 37.3% 201 0.8 2.7 0.5 122.4 14.4

Host Loss% Snt Last Avg Best Wrst StDev
1. seawa-prod-lb-v67.xxyyxxyy.com 34.4% 186 0.2 0.2 0.1 0.5 0.0
2. seawa-comm-fw1-e2-1.xxyyxxyy.c 34.6% 185 0.4 0.5 0.3 2.9 0.2
3. seawa-emer-fw1.xxyyxxyy.com 34.6% 185 5.0 1.2 0.4 26.3 2.5
4. wksx-ins1-prod.xxyyxxyy.com 34.6% 185 0.9 3.6 0.6 144.3 15.2

Host Loss% Snt Last Avg Best Wrst StDev
1. seawa-prod-lb-v67.xxyyxxyy.com 43.1% 281 0.2 0.2 0.1 1.7 0.1
2. seawa-comm-fw1-e2-1.xxyyxxyy.c 43.1% 281 0.3 0.5 0.3 4.4 0.5
3. seawa-emer-fw1.xxyyxxyy.com 42.9% 280 0.6 0.8 0.4 8.5 0.8
4. wksx-ins1-prod.xxyyxxyy.com 43.2% 280 0.7 1.1 0.5 7.9 1.3

Host Loss% Snt Last Avg Best Wrst StDev
1. seawa-prod-lb-v67.xxyyxxyy.com 39.3% 308 0.2 0.2 0.1 0.4 0.0
2. seawa-comm-fw1-e2-1.xxyyxxyy.c 39.3% 308 2.9 1.3 0.3 54.5 5.0
3. seawa-emer-fw1.xxyyxxyy.com 39.3% 308 3.4 0.9 0.5 7.2 0.9
4. wksx-ins1-prod.xxyyxxyy.com 39.0% 308 0.7 2.2 0.6 122.3 11.8Is it giving me any clue, I should check and narrow down this issue?

Thanks