Joined: 07 Jan 2025 Posts: 155 Location: Bethel Park, PA, USA
Posted: Wed Jan 08, 2025 1:54 Post subject:
HalfBit wrote:
Does anyone understand more fully why adding all multicast, or promiscuous (ifconfig eth0 promisc) on eth0 would help continue to obtain the default IPv6 route from an ISP?
I was looking into this but can't find anything in the prefix delegation process that uses multicast. The only thing I can figure is that some ISPs (Verizon in my case) are doing something non-standard. _________________ Formerly dpp3530 Linksys MR7350
Gateway, 2 wired APs, NSS-ECM , Clock 1440MHz
VAPs on wlan0 and wlan1 for guest/IOT devices
IPv4 & IPv6 (Prefix Delegation)
Static Leases & DHCP
SmartDNS (using NextDNS, Cloudflare), DNSMasq
Wireguard and OpenVPN server
2.4GHz: dd-wrt, N/G-Mixed, ACK Timing 1350, WPA3 SAE & WPA2 w/AES
5GHz: dd-wrt, AX/AC/N Mixed, ACK Timing 1350, WPA3 SAE & WPA2 w/AES
Verizon Fios, 500/500Mbps
Yes, precisely. What other information can I provide that might help with this? I'm willing to do what I can to help troubleshoot this.
I don't see the same problem on my R7000, so I'm not seeing evidence that it is an ISP issue. _________________ R7800 Nighthawk - DD-WRT v3.0-r58850 std (Primary)
R7800 Nighthawk - DD-WRT v3.0-r58389 std (Cold Secondary)
▲ ACTIVE / INACTIVE ▼
R7000 Nighthawk - DD-WRT v3.0-r58850 std (Still works great after running for 10 years solid)
R7000 Nighthawk - DD-WRT v3.0-r58850 std (Cold Secondary)
R7000 Nighthawk - DD-WRT v3.0-r58389 std (Extra)
~~~~~~~~~~Dismantled for learning opportunities~~~~~~~~~~
WRT54Gv2
WRT54Gv8.2
~~~~~~~~~~Other Settings~~~~~~~~~
https://nextdns.io/?from=2d3sq39x https://pi-hole.net/ https://github.com/DNSCrypt/dnscrypt-proxy
Joined: 07 Jan 2025 Posts: 155 Location: Bethel Park, PA, USA
Posted: Fri Jan 10, 2025 3:49 Post subject:
kernel-panic69 wrote:
Is it only on Linux 6.x builds? Does OpenWRT kernel 6.x builds have the same problem?
I don't have OpenWRT to try, but it started in r56326, which was a K6 build. I should add that it only happens when NSS cores are being used (NSS-ECM, NSS-SFE, or NSS-ECM-SFE), with Shortcut Forwarding disabled or set to SFE, no issue. NSS works if (Block) Multicast Communication is unchecked in the Security tab or if as @HalfBit said, you enable promiscious mode. Otherwise the one line in the routing table is missing as I said in the first post on this thread. _________________ Formerly dpp3530 Linksys MR7350
Gateway, 2 wired APs, NSS-ECM , Clock 1440MHz
VAPs on wlan0 and wlan1 for guest/IOT devices
IPv4 & IPv6 (Prefix Delegation)
Static Leases & DHCP
SmartDNS (using NextDNS, Cloudflare), DNSMasq
Wireguard and OpenVPN server
2.4GHz: dd-wrt, N/G-Mixed, ACK Timing 1350, WPA3 SAE & WPA2 w/AES
5GHz: dd-wrt, AX/AC/N Mixed, ACK Timing 1350, WPA3 SAE & WPA2 w/AES
Verizon Fios, 500/500Mbps
I don't have OpenWRT to try, but it started in r56326, which was a K6 build. I should add that it only happens when NSS cores are being used (NSS-ECM, NSS-SFE, or NSS-ECM-SFE), with Shortcut Forwarding disabled or set to SFE, no issue. NSS works if (Block) Multicast Communication is unchecked in the Security tab or if as @HalfBit said, you enable promiscious mode. Otherwise the one line in the routing table is missing as I said in the first post on this thread.
Good call. My R7800 can't renew the IPv6 default route during these conditions:
1. about 30 minutes after a reboot and eth0 has the default UP BROADCAST RUNNING MULTICAST configured/enabled, or
2. with NSS cores (NSS-ECM, NSS-SFE, or NSS-ECM-SFE) enabled, or
3. with Multicast filtering (Multicast Communication) enabled (checked) which I believe is also default
The IPv6 default route is perpetuated when:
1. I have ifconfig eth0 allmulti in my startup commands, or
2. I disable NSS cores (NSS-ECM, NSS-SFE, or NSS-ECM-SFE), or
3. I disabled (uncheck) Multicast filtering (Multicast Communication)
kernel-panic69 wrote:
Is it only on Linux 6.x builds? Does OpenWRT kernel 6.x builds have the same problem?
What additional information can I provide to troubleshoot, diagnose, or otherwise help the community figure this out? I've never tried OpenWRT, but is there a specific DDWRT build with a different kernel version you'd like me to flash and compare? I have two R7800s so I'm willing to do anything I can. One limitation is that I don't have a serial connection.
egc wrote:
One of my R7800 is running Openwrt and does not have this problem.
What do you do to mitigate this issue on your R7800(s) running DDWRT?
Per Yngve Berg wrote:
I can confirm that there where connection issues and Reboots with the early builds that had the NSS Cores Enabled. Fixed in later builds.
What version are you referring to, if you remember? Do you have a R7800? If so, what do you do to mitigate this issue on yours?
Side note for all of you. I was surprised to see that TCPDUMP was removed from the builds. Is there a guide for ENTWARE on R7800s that you all would recommend in case I need TCPDUMP to help figure out this issue? _________________ R7800 Nighthawk - DD-WRT v3.0-r58850 std (Primary)
R7800 Nighthawk - DD-WRT v3.0-r58389 std (Cold Secondary)
▲ ACTIVE / INACTIVE ▼
R7000 Nighthawk - DD-WRT v3.0-r58850 std (Still works great after running for 10 years solid)
R7000 Nighthawk - DD-WRT v3.0-r58850 std (Cold Secondary)
R7000 Nighthawk - DD-WRT v3.0-r58389 std (Extra)
~~~~~~~~~~Dismantled for learning opportunities~~~~~~~~~~
WRT54Gv2
WRT54Gv8.2
~~~~~~~~~~Other Settings~~~~~~~~~
https://nextdns.io/?from=2d3sq39x https://pi-hole.net/ https://github.com/DNSCrypt/dnscrypt-proxy
