A certain site WBC560, as an XAC-managed local forwarding AP wireless terminal, can ping public IPv6 domains but cannot open IPv6 pages.

WBC560 enables XAC function to manage AP--local forwarding--IPv4 and IPv6 dual stack

Previously, the site operated normally using pure IPv4 services. After the IPv6 upgrade, occasional issues occurred where wireless terminal access to APs bound to local forwarding services could ping IPv6 public domains but failed to open IPv6 pages, which would automatically recover after some time.

1. Field testing was conducted on the centralized forwarding service template, and the exact same phenomenon occurred.

2. The wireless terminal PC executed ping ipv6 to a public domain name in cmd. It was found that large packets could also be pinged successfully, but web pages still could not be opened, while ipv4 worked without issues.

ping -l 1402 -6 www.baidu.com // ping ipv6 packet, -l specifies the byte size

Pinging www.a.shifen.com [2408:873d:22:18ac:0:ff:b021:1393] with 1402 bytes of data:

Reply from 2408:873d:22:18ac:0:ff:b021:1393: time=16ms

Reply from 2408:873d:22:18ac:0:ff:b021:1393: time=15ms

Reply from 2408:873d:22:18ac:0:ff:b021:1393: time=18ms

Reply from 2408:873d:22:18ac:0:ff:b021:1393: time=16ms

3. The role of radio equipment is to transmit terminal packets to the gateway device. Generally, if commands such as ACL, packet-filter, or Qos are not configured, the system will not discard packets selectively. Therefore, it is recommended to troubleshoot the gateway and upstream devices on-site and perform mirror capture for analysis when necessary.

During troubleshooting, an alarm was detected on the IMC gateway platform indicating issues with the core switch device.

As shown in the Error alarm above, we logged into the core switch and found numerous alarm logs.

The following explanation was obtained from the community inquiry.

This indicates insufficient next hop resources on the core switch. During the failure, the next hop resources were exhausted, causing terminal access to IPv6 public domain resources to fail when opening web pages or loading related content, resulting in errors.

After contacting the core switch technical support for follow-up, the occasional issue of terminal IPv6 being unable to access public web pages was resolved.