On Thu, Nov 16, 2017 at 08:36:18PM +0000, Roderick wrote:
> But still I want to get the DNS from the ppp peer.
Then you need to ask your ISP for static nameserver IPs, or use
a umb(4) device, or implement this missing feature in sppp(8)
such that it decodes the relavant IPCP options passed by the
PPP session peer and makes the information available somehow.
See /usr/src/sys/net/if_spppsubr.c for relevant source code.
With my umsm(4) device, running 'tcpdump -n -i ppp0 -v' while
connecting, I see:
23:15:59.704894 IPCP: Configure-Nak, Unknown IPCP code 0x81
0308 001c 8106 0a0b 0c0d 8306 0a0b 0c0e
8206 0a0b 0c0d 8406 0a0b 0c0e
This seems to be one of several DNS related IPCP codes which
our sppp(4) driver ignores. According to Table 7.10 here:
https://technet.microsoft.com/en-us/library/cc957981.aspx
"Primary DNS server address | 129 or 0x81"
