tug.ctan.org inaccessible on a specific machine

Henri Menke henri at henrimenke.de
Fri Apr 2 13:46:03 CEST 2021


Ah, you're on a DigitalOcean VPS. They are very popular among scammers,
spammers, and for DDoS, so it's very likely that your IP is blocked
pretty much everywhere. Check whether you appear in any of the common
databases, e.g.

https://www.abuseipdb.com/

Cheers, Henri

On Fri, 2021-04-02 at 07:09 -0400, AC wrote:
> Here are the results of an mtr ping:
> 
> Start: 2021-04-02T03:33:06+0000
> HOST:
> gilead                                                               
>  Loss%   Snt   Last   Avg  Best  Wrst StDev
>   1.
> AS???    ???                                                         
>   100.0   100    0.0   0.0   0.0   0.0   0.0
>   2.
> AS???    10.74.132.77                                                
>    0.0%   100    0.5   0.9   0.4  29.9   3.0
>   3.
> AS???    138.197.248.232                                             
>    0.0%   100    1.1   2.3   0.7  36.6   4.9
>   4.
> AS???    138.197.248.12                                              
>    0.0%   100    0.6   1.8   0.3  61.5   7.4
>   5.
> AS???    138.197.244.46                                              
>    0.0%   100    0.9   1.1   0.8   4.4   0.5
>   6.
> AS14061  162.243.191.247                                             
>    0.0%   100    0.9   1.5   0.9  36.5   3.7
>   7. AS6461   ae18.cs1.lga5.us.zip.zayo.com
> (64.125.27.178)                 99.0%   100   48.4  48.4  48.4  48.4 
>   0.0
>   8. AS6461   ae3.cs3.ord2.us.eth.zayo.com
> (64.125.29.209)                  88.0%   100   50.9  49.1  48.4  50.9
>    0.7
>   9.
> AS???    ???                                                         
>   100.0   100    0.0   0.0   0.0   0.0   0.0
>  10. AS6461   ae11.mpr2.slc2.us.zip.zayo.com
> (64.125.26.43)                  0.0%   100   48.3  49.1  48.1  75.9  
>  3.5
>  11. AS6461   ae4.mpr1.slc2.us.zip.zayo.com
> (64.125.26.164)                  0.0%   100   47.6  48.4  47.6  65.2 
>   2.3
>  12. AS6461   209.66.120.134.IPYX-246177-ZYO.zip.zayo.com
> (209.66.120.134)   0.0%   100   48.3  49.1  48.2  65.4   3.1
>  13.
> AS210    140.197.253.110                                             
>    0.0%   100   49.5  49.6  49.4  50.1   0.1
>  14.
> AS210    140.197.252.76                                              
>    0.0%   100   49.7  49.6  49.3  50.1   0.1
>  15.
> AS210    140.197.252.84                                              
>    0.0%   100   50.9  49.7  49.3  52.0   0.5
>  16.
> AS210    140.197.253.139                                             
>    0.0%   100   49.4  49.3  49.2  50.1   0.1
>  17.
> AS17055  199.104.93.117                                              
>    0.0%   100   49.6  49.6  49.5  50.2   0.1
>  18.
> AS17055  199.104.93.102                                              
>    0.0%   100   50.1  50.7  50.0  63.7   1.9
>  19.
> AS17055  155.99.130.59                                               
>    0.0%   100   50.2  50.1  50.0  50.7   0.1
>  20.
> AS17055  155.99.130.14                                               
>    0.0%   100   50.4  50.4  49.9  62.9   1.7
>  21.
> AS???    ???                                                         
>   100.0   100    0.0   0.0   0.0   0.0   0.0
> 
> ---
> 
> I am certainly *not* on ip6, and my VPS admins advise as follows:
> 
> > Thank you for following up and sharing the mtr results. As per the
> > mtr results, the destination domain "tug.ctan.org" is not
> > reachable. As we are able to ping from other droplets, I suspect
> > the issue is that your droplet's IP address is blocked at the
> > destination.
> > 
> > As the packets are moving out of DigitalOcean' network (AS14061)
> > and traversing to the destination, this isn't an issue at the
> > DigitalOcean managed network. You will need to contact the
> > administrator of the domain "tug.ctan.org" and request them to
> > check if the droplet's IP is blacklisted for some reason and
> > request them to delist.
> > 
> 
> This is what it looks like to me too: there's every indication that
> tug.ctan.org is specifically blocking this IP. I simply do not see
> how the issue could be at my end..
> 
> Whom would I contact about that? 
> 
> I am not sure who controls tug.ctan.org, and whether someone who
> could un-blacklist me is reading this.
> 
> On April 2, 2021 6:56:13 AM EDT, Zdenek Wagner <
> zdenek.wagner at gmail.com> wrote:
> > Hi all,
> > 
> > I tried to ping tug.ctan.org without specifying the protcol and
> > with
> > IPv6 requested. This is my result:
> > 
> > [zw at math-gnostics ~]$ ping -c5 tug.ctan.org
> > PING ftp.math.utah.edu (155.101.98.136) 56(84) bytes of data.
> > 64 bytes from ftp.math.utah.edu (155.101.98.136): icmp_seq=1 ttl=33
> > time=154 ms
> > 64 bytes from ftp.math.utah.edu (155.101.98.136): icmp_seq=2 ttl=33
> > time=154 ms
> > 64 bytes from ftp.math.utah.edu (155.101.98.136): icmp_seq=3 ttl=33
> > time=154 ms
> > 64 bytes from ftp.math.utah.edu (155.101.98.136): icmp_seq=4 ttl=33
> > time=154 ms
> > 64 bytes from ftp.math.utah.edu (155.101.98.136): icmp_seq=5 ttl=33
> > time=154 ms
> > 
> > --- ftp.math.utah.edu ping statistics ---
> > 5 packets transmitted, 5 received, 0% packet loss, time 4007ms
> > rtt min/avg/max/mdev = 153.873/153.980/154.067/0.077 ms
> > [zw at math-gnostics ~]$ ping -c5 -6 tug.ctan.org
> > ping: tug.ctan.org: Address family for hostname not supported
> > 
> > So the reason for timeout must be somewhere else, not in IPv6, the
> > program would inform about it.
> > 
> > Zdeněk Wagner
> > http://ttsm.icpf.cas.cz/team/wagner.shtml
> > http://icebearsoft.euweb.cz
> > 
> > pá 2. 4. 2021 v 11:36 odesílatel Henri Menke via tex-live
> > <tex-live at tug.org> napsal:
> > > On 01/04/21, 23:17, AC wrote:
> > > > Well, I know it's accessible, but the problem is specific to
> > > > this
> > pair of IPs.. I can ping
> > > > - google.com just fine from that affected machine, and
> > > > - tug.ctan.org from any other IPs I control (like my home
> > computers).
> > > > Could it be that the server is rejecting my connection (from
> > > > that
> > specific IP) due to some misconfiguration?
> > > Could it be that you are on an IPv6 only network? The domain
> > > tug.ctan.org only returns an IPv4 address.
> > > 
> > > Nevertheless, the problem is definitely on your side.
> > > 
> > > Cheers, Henri
> > > 
> > > > On April 1, 2021 11:02:54 PM EDT, Norbert Preining
> > <norbert at preining.info> wrote:
> > > > > On Thu, 01 Apr 2021, AC wrote:
> > > > > > ping tug.ctan.org
> > > > > > - time out on the affected machine, but
> > > > > 
> > > > > Nothing we can help you there. If you have root access, you
> > > > > can
> > try
> > > > > traceroute to see where it hangs. The server is definitely
> > accessible.
> > > > > Best
> > > > > 
> > > > > Norbert
> > > > > 
> > > > > --
> > > > > PREINING Norbert                             
> > https://www.preining.info
> > > > > Fujitsu                 + IFMGA Guide + TU Wien + TeX Live +
> > Debian Dev
> > > > > GPG: 0x860CDC13   fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448
> > > > > 860C
> > DC13



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