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Some web sites not loading

Grff
Grafter
Posts: 359
Thanks: 2
Registered: ‎02-08-2007

Some web sites not loading

Hi guys, I'm after a bit of help.
I've replaced the TG852 router with our Sonicwall, and it connects over PPPOE fine, and our three VPN's are working ok to this office.
However, when someone at the remote office browses the web, sometimes site are either slow to load, or just won't load and IE is telling me waiting for the site to respond.
Three examples are speedtest.net, dorsetecho.co.uk, and unfortunately our own site, canford.co.uk
I've left the Sonicwall's connection to auto assign IP (as it's static from plusnet)  Clients get their DHCP from the Sonicwall, are assigned DNS IP's of our Domain Controller, which than has forwarders set to PlusNet's DNS.
NSLookups are all fine and seem to be quick.
When I do a tracert to some problematic sites I get;
C:\Users\Administrator.CANFORD_GROUP>tracert www.dorsetecho.co.uk
Tracing route to m6-lb.newsquestdigital.co.uk [62.233.114.118]
over a maximum of 30 hops:
 1    16 ms    17 ms    17 ms  lo0-central10.pcl-ag01.plus.net [195.166.128.182]
 2    16 ms    16 ms    16 ms  link-b-central10.pcl-gw02.plus.net [212.159.2.162]
 3    15 ms    15 ms    15 ms  xe-10-0-0.pcl-cr02.plus.net [212.159.0.194]
 4    16 ms    16 ms    16 ms  ae2.pcl-cr01.plus.net [195.166.129.6]
 5    15 ms    15 ms    15 ms  ae1.ptw-cr01.plus.net [195.166.129.0]
 6     *        *        *     Request timed out.
 7    25 ms    26 ms    25 ms  no-ptr.as20860.net [62.233.127.242]
 8    26 ms    26 ms    26 ms  no-ptr.as20860.net [62.233.118.230]
 9    29 ms    25 ms    25 ms  no-ptr.as20860.net [62.233.127.246]
10    25 ms    25 ms    59 ms  no-ptr.as20860.net [62.233.118.221]
11    26 ms    25 ms    25 ms  62.128.192.197
12    25 ms    25 ms    24 ms  62.128.192.194
13    25 ms    25 ms    25 ms  no-ptr.as20860.net [62.233.127.178]
14    28 ms    27 ms    31 ms  m6-lb.newsquest.co.uk [62.233.114.118]
Trace complete.
--------------------------------------------------------
C:\Users\Administrator.CANFORD_GROUP>tracert www.canford.co.uk
Tracing route to www.canford.co.uk [195.97.254.131]
over a maximum of 30 hops:
 1    72 ms    23 ms    23 ms  lo0-central10.pcl-ag01.plus.net [195.166.128.182]
 2    16 ms    16 ms    16 ms  link-a-central10.pcl-gw01.plus.net [212.159.2.160]
 3    15 ms    15 ms    15 ms  xe-10-0-0.pcl-cr01.plus.net [212.159.0.192]
 4    16 ms    15 ms    16 ms  ae1.ptw-cr01.plus.net [195.166.129.0]
 5    15 ms    16 ms    15 ms  ae2.ptw-cr02.plus.net [195.166.129.5]
 6     *        *        *     Request timed out.
 7    25 ms    25 ms    24 ms  ge0-1.thlon-cr01.onyx.net [194.176.73.18]
 8    24 ms    24 ms    25 ms  ge0-3.dbncl-cr01.onyx.net [195.97.199.2]
 9    24 ms    24 ms    24 ms  ge0-3.dbncl-er05.onyx.net [194.176.72.60]
10  ^C
(Cancelled the tracert as our server doesn't reply to pings).

Anyone any ideas?
Thanks
Carl
4 REPLIES 4
Pettitto
Plusnet Alumni (retired)
Plusnet Alumni (retired)
Posts: 6,346
Fixes: 5
Registered: ‎26-11-2011

Re: Some web sites not loading

Hi Carl,
Out of interest, do you get the same issue with the TG582n?
Grff
Grafter
Posts: 359
Thanks: 2
Registered: ‎02-08-2007

Re: Some web sites not loading

Didn't 'notice' any issue when it was tried with an ipad and the TG582. I think I may have to get someone to put the TG582 back in and test it with a wired laptop.
Unfortunately it means rejigging my VPN's, and other settings again changing everything back to Onyx for a while.
Can I use PlusNet's DNS if I'm not connected to it? Saves having to change my Domain Controllers again too.
bobpullen
Community Gaffer
Community Gaffer
Posts: 16,869
Thanks: 4,950
Fixes: 315
Registered: ‎04-04-2007

Re: Some web sites not loading

Quote from: Griff
Can I use PlusNet's DNS if I'm not connected to it? Saves having to change my Domain Controllers again too.

Connected to what? The 582n? You can use pretty much any router of your choosing with our DNS servers. You need to be connected to a Plusnet broadband line in order to query them though.

Bob Pullen
Plusnet Product Team
If I've been helpful then please give thanks ⤵

Grff
Grafter
Posts: 359
Thanks: 2
Registered: ‎02-08-2007

Re: Some web sites not loading

Bob, I was referring to using Plusnet's DNS server if I was sending my traffic down my Onyx internet line.  I was going to revert back to my Onyx line, and to save time leave my servers DNS set to Plusnet
I think I may have solved the issue.  My Sonicwall PPPOE connection had it's MTU setting at 1500 (default).  I reduced that to 1492, and the sites I was having problems with seemed to be all loading fine now, and fairly quickly too.
The tracert still timeout at the same hop, but I'll keep an eye on it and see if that's all it was.
Quote
The maximum transmission unit, here on referred to as MTU, is the maximum amount of bytes that can be encapsulated in an IP packet. The MTU size includes the data payload, any transport headers (such as TCP, UDP, GRE, RTP, or ICMP), and the IP header.
It is generally recommended that the MTU for a WAN interface connected to a PPPoE DSL network be 1492. In fact, with auto MTU discovery, 1492 is discovered to be the maximum allowed MTU. However, having an MTU of 1452 is most optimal.
The maximum MTU for Ethernet connections on SonicWALL devices is 1500 bytes (Ethernet maximum MTU size).  Having an MTU of 1500 allows for 1460 bytes of data payload, 20 bytes of TCP header, and 20 bytes of IP header. With PPPoE connections, the PPP and PPPoE header increases the frame size by 8 bytes, so we must lower the MTU to 1492.