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Maggiore81
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IPv6 Fastpath on 7.18

Tue Mar 04, 2025 11:03 am

Hello
did anyone has success implementing IPv6 fastpath on 7.18+ ?
I have met the same conditions as fastpath ipv4, the checkbox is active, but no counters! All to 0.
How can I be sure the fastpath is running?

thanks
 
un9edsda
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Re: IPv6 Fastpath on 7.18

Tue Mar 04, 2025 1:19 pm

Have you applied the command and the two rules (at the right spot) that @BrateloSlava and restarted the router as @Sit75 have suggested in the 7.18 beta thread?

Edit:
you may also have a look at @CGGXANNX's note about IPv6 and TCP MSS and @felixka's post about IPsec interaction with IPv6 FastPath.
 
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Maggiore81
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Re: IPv6 Fastpath on 7.18

Tue Mar 04, 2025 2:25 pm

Hello, thank you for your reply. I have no issue with fasttrack-v6, I was talking about fastPATH
 
un9edsda
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Re: IPv6 Fastpath on 7.18

Tue Mar 04, 2025 2:54 pm

[...] I was talking about fastPATH
My bad. Tough if FastTrack works for you, than FastPath should be too, since the former can't operate without the later. While we at the topic of FastPath (and FastTrack) the relevant sections of the documentation need some love, since IPv6 FastPath and FastTrack are undocumented features currently.
 
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Maggiore81
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Re: IPv6 Fastpath on 7.18

Tue Mar 04, 2025 3:14 pm

Fasttrack works, but even with NO RULES in the ipv6 section, the fastpath counter doesnt raise.
 
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dang21000
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Re: IPv6 Fastpath on 7.18

Tue Mar 04, 2025 11:19 pm

For, me, like in ipv4, fastpath counter stay always at 0.... but fastrack work well :
[admmikrotik@router70a] > /ip/settings/print   
                                 ip-forward: yes          
                             send-redirects: yes          
                        accept-source-route: yes          
                           accept-redirects: no           
                           secure-redirects: yes          
                                  rp-filter: strict       
                 ipv4-multipath-hash-policy: l3           
                             tcp-syncookies: yes          
                             tcp-timestamps: random-offset
                       max-neighbor-entries: 16384        
                                arp-timeout: 30s          
                            icmp-rate-limit: 100000       
                             icmp-rate-mask: 0x1818       
  icmp-errors-use-inbound-interface-address: no           
                            allow-fast-path: yes          
                      ipv4-fast-path-active: no           
                     ipv4-fast-path-packets: 0            
                       ipv4-fast-path-bytes: 0            
                      ipv4-fasttrack-active: yes          
                     ipv4-fasttrack-packets: 1202060      
                       ipv4-fasttrack-bytes: 1250656041   
[admmikrotik@router70a] > /ipv6/settings/print 
                    disable-ipv6: no        
                         forward: yes       
           multipath-hash-policy: l3        
                accept-redirects: no        
    accept-router-advertisements: no        
      disable-link-local-address: no        
  stale-neighbor-detect-interval: 30        
          stale-neighbor-timeout: 60        
            min-neighbor-entries: 4096      
       soft-max-neighbor-entries: 8192      
            max-neighbor-entries: 16384     
                 allow-fast-path: yes       
           ipv6-fast-path-active: yes       
          ipv6-fast-path-packets: 0         
            ipv6-fast-path-bytes: 0         
           ipv6-fasttrack-active: yes       
          ipv6-fasttrack-packets: 7301486   
            ipv6-fasttrack-bytes: 7933132583
 
dave3
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Re: IPv6 Fastpath on 7.18

Fri Mar 21, 2025 4:18 am

I'm on 7.18.2, trying to enable IPv6 fast track, but in winbox, the setting is blank and it won't let me enable it.

Image

Is the only way to enable it, to manually add a firewall rule (as suggested earlier)?
/ipv6 firewall filter add action=fasttrack-connection chain=forward comment="Enable FastTracked v6 traffic" connection-state=established,related
/ipv6 firewall filter add action=accept chain=forward comment="accept established,related,untracked" connection-state=established,related,untracked
The second rule is already present, but not the first.
 
CGGXANNX
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Re: IPv6 Fastpath on 7.18

Fri Mar 21, 2025 7:24 am

Yes, you'll need both rules. Also, as documented by @EdPa from MikroTik, some bridge settings like DHCP Snooping cause fast path to be ineffective, as a result, fasttrack will also not work on that bridge (shown as active but the counters do not increase), in those cases you'll only get "partial" fasttracking when moving packets between bridge and (WAN) interfaces external to the bridge only, not for inter-VLAN traffics (if you keep DHCP Snooping enabled).
 
dave3
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Re: IPv6 Fastpath on 7.18

Fri Mar 21, 2025 8:50 am

Thanks, I deleted all the old rules, inserted the new "fasttrack-connection" rule at the top of the "forward" chain that I exported, and reapplied all of the rules, and rebooted.

It looks like it's working now.

Image
 
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Maggiore81
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Re: IPv6 Fastpath on 7.18

Fri Mar 21, 2025 3:22 pm

that is FASTTRACK, on my OP, I wrote FAST PATH!
no rules, just packets from one int to another.
 
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NathanA
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Re: IPv6 Fastpath on 7.18

Mon Mar 24, 2025 1:59 am

I've been pretty negative recently in my posts here (I would argue justifiably, though that's neither here nor there at the moment), but I want to take a moment to offer well deserved praise and give credit where credit is due. So: THANK YOU MikroTik (genuinely) for FINALLY getting around to implementing IPv6 Fastpath/Fasttrack support. The lack of this has been a HUGE showstopper in doing a major IPv6 push to most of our end-users, since we have deployed a LOT of RouterBOARDs to customers as CPE. And prior to this, IPv6 forwarding performance was notably worse than IPv4 (which has had FP/FT for forever now).

However... 🙂

My experience has been largely the same as most others here with 7.18(.2), which is that I can get IPv6 FastTRACK to work great, but FastPATH does not *seem* to work.

Now, perhaps this is completely a cosmetic/reporting bug, and IPv6 Fastpath actually works just fine; I have not yet taken time to measure actual performance to see if that is the case. But, if I have IPv6 connection tracking turned off, zero IPv6 filter/NAT/mangle rules defined, and '/ipv6/settings/allow-fast-path=yes', then it will show 'ipv6-fast-path-active: yes', BUT the 'ipv6-fast-path-packets' and 'ipv6-fast-path-bytes' counters do NOT budge from 0 at *all*.

If this is just a cosmetic bug, it's very different from the one afflicting IPv4 FP/FT in 7.18, where Fasttrack works and the counters count up, but it says 'ipv4-fasttrack-packets: NO'. I understand this reporting error is fixed in 7.19beta.

I haven't been super bothered by (apparent) lack of working IPv6 Fastpath in 7.18.x, since we are largely deploying this on customer CPE where it's pretty important to have some common-sense firewall rules in place, so IPv6 connection tracking has to be on, and thus we take advantage of Fasttrack instead, which seems to work fine. But since Fastpath is supposed to be a headlining feature, and since it would be nice to see this working properly on, say, CCR hardware that's sitting on our network and forwarding IPv6 traffic to end-users, I am adding my "me too" to this report. (And if IPv6 Fasttrack works but Fastpath doesn't, that is kind of a shocking thing to have slide through the QA for this 7.18 release, where IPv6 Fastpath was pretty heavily promoted. Like, how does such a bug not get caught on the way out the door...)