Frequently Asked Questions And Compliance Suggestions On Ip Allocation And Management Of Korean Kt Station Group

1.

kt station group ip allocation basic model and common restrictions

- kt usually uses /29 or /28 as the smallest visible allocation unit, and a common block given to hosting customers is /29 (6 available addresses).
- ipv4 resources are scarce. operators will audit the ip usage under the same asn. if the usage exceeds the threshold, it may be recycled.
- common practices for multi-station group management: bgp multicast or nat + port forwarding to save public ip.
- compliance risk: a large number of similar sites use a single /29, leading to abuse complaints, and whois and ptr records need to be consistent.
- recommendation: prepare business description, anti-spam policy and abuse handling process when applying, and cooperate with kt to provide ptr and reverse analysis.

2.

ip management and routing configuration example (technical details)

- example: assign network segment 203.0.113.8/29, available addresses 203.0.113.9-203.0.113.14 (6).
- router configuration (bgp example): neighbor xxxx remote-as y; network 203.0.113.8/29; persistent community tags are used for filtering.
- nat solution: the internal 10.0.0.0/24 egress uses 203.0.113.9 for pat to reduce public ip consumption.
- nginx reverse proxy configuration example: worker_processes 4; worker_connections 1024; upstream keepalive 32;.
- logging and monitoring: it is recommended to enable netflow/sflow collection and set threshold alarms. if the traffic exceeds 80% of the bandwidth peak in 30 minutes, an audit will be automatically triggered.

3.

domain name and reverse resolution (ptr) and compliance points

- ptr must be consistent with whois/website information to avoid being marked as suspicious by anti-spam or security vendors.
- when multiple domain names resolve to the same ip, it is recommended to set ptr for the main site and use an independent sending ip in the email header.
- the whois information needs to be filled in with the real contact person and the abuse email address. kt has strict requirements on the response time of the abuse email address (usually within 48 hours).
- tls/certificate management: it is recommended that each site use independent certificates or use san/wildcard, but mail and mx should use independent public ips.
- compliance recommendation: keep connection and change logs for 90 days for regulatory and abuse investigations.

4.

ddos defense and cdn linkage practice

- common practice: connect to cdn (such as cloudflare, akamai or local cdn) as the first line of defense to mitigate l7 and some l3/l4 attacks.
- line-level protection: kt can provide black hole routing or traffic cleaning (for a fee). it is recommended that the peak traffic threshold be configured as 70% of the link.
- local protection: deploy hardware protection (such as fpga acceleration) or software current limiting (iptables connlimit, nf_conntrack).
- real-time policy: enable rate limiting, geoip blocking and js challenges, combined with waf rules to prevent layer7 attacks.
- monitoring example: set an alarm when syn packets exceed 100k within 1 minute, and automatically issue an acl to the upstream to block the source.

5.

real case: site group abuse incident and resolution of a korean hosting provider

- background: company a, a hosting provider, uses 5/29 allocated by kt to host website groups for customers, totaling 30+ websites.
- problem: 8 of the sites were used to send spam, causing kt to receive an abuse complaint and impose temporary traffic restrictions on asn.
- disposal: company a enabled an independent email export ip, adjusted ptr, banned abusive customers and submitted a rectification report to kt within 24 hours.
- outcome: kt lifted traffic restrictions and required company a to provide abuse prevention and monitoring procedures within 90 days.
- enlightenment: separating email traffic from website traffic in advance and establishing a 24/7 abuse response process can significantly reduce the risk of being recycled.

6.

management tools and automated recommendations

- it is recommended to use ipam (such as phpipam or netbox) to manage allocation and tags to maintain traceability of the address pool.
- automation script: use ansible to manage bgp/firewall rules and regularly synchronize ptr and dns records.
- log aggregation: use elk/efk to centralize logs and set abuse rules to automatically alert (for example, the number of abnormal connections exceeds 1,000 per hour).
- audit and compliance: export ip usage reports regularly (monthly) and maintain consistency with kt's sla document.
- backup strategy: configure off-site backup of the control plane and configuration files. 7×24 disaster recovery drills are recommended.

7.

sample data table: kt pop ip pool allocation diagram

pop location	/29 quantity	available public ip	recommended use
seoul (seoul-1)	4	twenty four	web frontend + reverse proxy
busan (busan-1)	2	12	email export and cdn return to origin
daegu (daegu-1)	1	6	manage and monitor exports

- the examples in the table are for demonstration purposes. the actual application to kt is subject to the operator's reply;