hi guys
I have two Synology routers (router1 and router2) and two internet connections (ISP1 and ISP2). I set up L2TP VPN on both routers and I use it with the macOS built in L2TP VPN client. My problem is that I’m getting “authentication failed” error message but only when I try to connect from router1/ISP1 to router2/ISP2. (both works from outside)
To sum up:
– when I’m connected to router2 and ISP2, I CAN connect via VPN to router1 and ISP1
– when I’m on my iPhone via cellular data, I CAN connect via VPN to BOTH router1/ISP1 and router2/ISP2 without problems
– when I’m connected to router1 and ISP1, I CANNOT connect via VPN to router2 and ISP2 (I get authentication failed error message).
yes the usernames, passwords and pre shared keys are correct. Checked 20 times and it works great from my phone via cellular data on both routers.
Both routers have the same firewall settings. I tried it even with firewall completely turned off, still does not work. Other settings are basically identical on both routers, except DHCP server.
I tried this on 3 different Macs and also a Windows machine. Same results across all devices.
Here is the Mac console log (changed domain name, username and IPs):
Tue May 12 03:57:13 2020 : publish_entry SCDSet() failed: Success!
Tue May 12 03:57:13 2020 : publish_entry SCDSet() failed: Success!
Tue May 12 03:57:13 2020 : l2tp_get_router_address
Tue May 12 03:57:13 2020 : l2tp_get_router_address 1.1.1.1 from dict 1
Tue May 12 03:57:13 2020 : L2TP connecting to server ‘domainname.com’ (111.222.333.444)…
Tue May 12 03:57:13 2020 : IPSec connection started
Tue May 12 03:57:13 2020 : IPSec phase 1 client started
Tue May 12 03:57:13 2020 : IPSec phase 1 server replied
Tue May 12 03:57:14 2020 : IPSec phase 2 started
Tue May 12 03:57:14 2020 : IPSec phase 2 established
Tue May 12 03:57:14 2020 : IPSec connection established
Tue May 12 03:57:14 2020 : L2TP sent SCCRQ
Tue May 12 03:57:14 2020 : L2TP received SCCRP
Tue May 12 03:57:14 2020 : L2TP sent SCCCN
Tue May 12 03:57:14 2020 : L2TP sent ICRQ
Tue May 12 03:57:18 2020 : L2TP received ICRP
Tue May 12 03:57:18 2020 : L2TP sent ICCN
Tue May 12 03:57:18 2020 : L2TP connection established.
Tue May 12 03:57:18 2020 : L2TP set port-mapping for en1, interface: 5, protocol: 0, privatePort: 0
Tue May 12 03:57:18 2020 : using link 0
Tue May 12 03:57:18 2020 : Using interface ppp0
Tue May 12 03:57:18 2020 : Connect: ppp0 <–> socket[34:18]
Tue May 12 03:57:18 2020 : sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x37637f67> <pcomp> <accomp>]
Tue May 12 03:57:18 2020 : L2TP port-mapping for en1, interfaceIndex: 0, Protocol: None, Private Port: 0, Public Address: 100010b, Public Port: 0, TTL: 0.
Tue May 12 03:57:18 2020 : L2TP port-mapping update for en1 indicates no NAT. Public Address: 100010b, Protocol: None, Private Port: 0, Public Port: 0
Tue May 12 03:57:18 2020 : L2TP port-mapping for en1 inconsistent. is Connected: 1, Previous interface: 5, Current interface 0
Tue May 12 03:57:18 2020 : L2TP port-mapping for en1 initialized. is Connected: 1, Previous publicAddress: (0), Current publicAddress 100010b
Tue May 12 03:57:18 2020 : L2TP port-mapping for en1 fully initialized. Flagging up
Tue May 12 03:57:18 2020 : rcvd [LCP ConfReq id=0x1 <mru 1400> <asyncmap 0x0> <auth chap MS-v2> <magic 0xde6b537f>]
Tue May 12 03:57:18 2020 : lcp_reqci: returning CONFACK.
Tue May 12 03:57:18 2020 : sent [LCP ConfAck id=0x1 <mru 1400> <asyncmap 0x0> <auth chap MS-v2> <magic 0xde6b537f>]
Tue May 12 03:57:21 2020 : sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x37637f67> <pcomp> <accomp>]
Tue May 12 03:57:21 2020 : rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x37637f67> <pcomp> <accomp>]
Tue May 12 03:57:21 2020 : sent [LCP EchoReq id=0x0 magic=0x37637f67]
Tue May 12 03:57:21 2020 : rcvd [CHAP Challenge id=0x84 <643716088031d3013f0211690cb9707e>, name = “l2tpd”]
Tue May 12 03:57:21 2020 : sent [CHAP Response id=0x84 <164d2ddca2358fa7e577d18d54ba9c9e00000000000000009de68ce3accb5dd8d3fb9e3d652247843ed5a62869cf8c3500>, name = “User name”]
Tue May 12 03:57:21 2020 : rcvd [LCP EchoRep id=0x0 magic=0xde6b537f]
Tue May 12 03:57:22 2020 : rcvd [CHAP Failure id=0x84 “”]
Tue May 12 03:57:22 2020 : MS-CHAP authentication failed:
Tue May 12 03:57:22 2020 : sent [LCP TermReq id=0x2 “Failed to authenticate ourselves to peer”]
Tue May 12 03:57:22 2020 : Connection terminated.
Tue May 12 03:57:22 2020 : L2TP disconnecting…
Tue May 12 03:57:22 2020 : L2TP sent CDN
Tue May 12 03:57:22 2020 : L2TP sent StopCCN
Tue May 12 03:57:22 2020 : L2TP clearing port-mapping for en1
Tue May 12 03:57:22 2020 : L2TP disconnected
Thank you for taking the time to read this