firewall - Why open 123/udp in both directions? - Super User
2022年6月22日 · (Linux PCs being able to use NTP, but Windows PCs mysteriously not receiving any replies, and it always turned out to be a port-123 firewall rule.) Dynamically assigned ports …
Why does NTP require bi-directional firewall access to UDP port …
2014年6月2日 · When operating in symmetric modes (1 and 2), this field must contain the NTP port number PORT (123) assigned by the IANA. Since the client's source port is 123, when the …
NTP: Common issues and troubleshooting - Cisco Community
2009年6月10日 · Confirm UDP port 123 is open throughout the network for NTP packets. Alternate design option . If you have a high end router, use it as a "NTP master" and have it …
Change source port of NTP requests on router using iptables
2017年2月20日 · iptables -t nat -I POSTROUTING -p udp -m udp --sport 123 -j MASQUERADE --to-ports 60000-61000. AT&T blocks outbound UDP traffic with source port 123, to mitigate …
ubuntu - What are the iptables rules to permit ntp? - Super User
2010年5月16日 · in any case, NTP is UDP port 123, so, assuming you are a CLIENT and want to access NTP servers you'd do: iptables -A OUTPUT -p udp --dport 123 -j ACCEPT iptables -A …
NTP sync fails but NTP servers are reachable on Windows 10
2024年4月2日 · Opening port 123 in the router firewall; Changing DNS settings (I use DNS-over-TLS) and have not gotten it to work. My router is on a double NAT configuration (i.e. Internet - …
Switch UDP 123 Port OPEN - Cisco Community
Our Switch (3750 & nexus 5000 & nexus 7000) be scan with udp 123 and 161 port open on management interface. I know it's open for NTP and SNMP.
Opening UDP port 123 - Cisco Community
2004年7月6日 · Good morning, I've been having problems with external NTP time servers not responding, causing time sync problems in our network. Can someone tell me the best way to …
Can I setup my OpenVPN home server on port 123 udp?
2024年10月9日 · You can set up OpenVPN on any UDP port number you like, it doesn't care; but. it might break Synology's own NTP access, depending on which NTP software it uses, …
Allowing Outbound UDP 123 - Security Implications? - Super User
2015年9月30日 · What are the risks of allowing outbound UDP 123 for an internal server (archive server) to synchronize with the external NTP server. Our internal server always displays …