SMS has a mission-critical role in modern business— many high-priority applications, alerts, and content depend heavily on an SMS being delivered in a timely manner. SMS is considered to be one of the safest channels for the transmission of critical information to a phone. It works on any handset, in any country, and it is still used often by recipients than many other channels.

But it’s deliverability is not flawless. The telecom industry is not fully interoperable and the optimal path for delivery is not always the one you are using. However, there are proven techniques that you can use to improve SMS delivery.

Use Numeric Sender IDs: Avoid using alphanumeric sender IDs in countries where telecom restrictions don’t allow the use; most carriers spam filters, alphanumeric senders. Instead, use numeric senders in international format (e.g. 397525856425). 

Don’t Spam: Not only is it illegal, more often than not, it doesn’t work. Most likely the message will not arrive at the handset and you will still be paying for it. Spam filters have become very effective at detecting spam attacks.

Randomize the Body of the Message: As we have seen with sender IDs, it is better to randomize the body of the message, if you can. If you are sending a campaign or password code, come up with more than one version of the content and change it randomly. 

For example:
Message 1: Your Pin Code is 2234
Message 2: Please enter 6765 into your application to verify your account

Randomize Sender ID: Some carriers will block repeated messages from the same sender, be they numeric or alphanumeric. To achieve optimal performance, get enough numeric senders in international format and then rotate them randomly for each message you send. This differs from country to country telecom restrictions. 

Provide Opt-Out details in SMS: For any Marketing/Promotional SMS, it’s always good to add opt-out details. This gives more credibility to your messages and reduces the chances of getting blocked by carriers.

To summarize, here are the key points to keep in mind:

• Use numeric sender IDs in international format
• Avoid alphanumeric senders
• Randomize sender and content
• Don’t spam

There are many restrictions placed by Network operators to filter our SPAM messages or to comply with local regulations. The complete list of countries & restrictions is mentioned below in the section “SMS Restrictions”. If a country is not mentioned in the below list, it means that the country does not have any known restrictions for sending messages. However, it’s advisable to follow the best practices mentioned above for all countries.

Country-Specific SMS Restrictions

1. Albania – Albanian Mobile Communications (AMC Mobil) filters for alphanumeric sender ID’s. We recommend using a numeric sender ID that does not start with a 0 to bypass the AMC Mobil filter.

2. Algeria – Orascom Telecom Algerie Spa (Djezzy 60302) filters local (i.e. Algerian domestic) sender IDs and also possibly alphanumeric sender ID’s. To bypass the Djezzy filter, we suggest using an international format numeric sender ID.

3. Argentina – Nextel Argentina (722020) does not provide DLR’s, hence Delivery Receipts should not be expected for messages sent to this network.
   
   Number formatting – When sending messages to Argentina you should ensure the 9 (normally used for an international voice call to an Argentinian mobile) between the country code and the local number is always omitted: Country Code 54 + 10 digit local number.

4. Azerbaijan – Use of Sender ID is generally not allowed by carriers. Sender ID will be changed to a random numeric string in messages sent to Barkcell Azerbaijan (40002) and Azerfon (Nar Mobile) (40004) to avoid messages getting caught by their filters. 

5. Bahrain – Messages to all networks in Bahrain (MCC=426) are being sent over a direct link between 09:00 A.M. and 8:00 P.M. according to the Kingdom of Bahrain’s timing. This route is fully featured, supports DLRs and dynamic senderID. Outside of these hours, an alternative link will be used. As always, political, religious, or adult content is likely to be blocked by the Bahraini operators.

6. Bangladesh – All message sender ID’s in messages sent to Bangladesh networks will be changed to a local Number (in international format) to ensure message delivery, as Bangladesh networks are heavily filtering on Sender ID’s.

7. Belgium – Any non-supported sender IDs will be changed to a shortcode.

8. Brazil – Brazil networks either don’t support handset DLR’s or provide them only sporadically. We recommend that you not rely on handset DLR in Brazil. Concatenated, binary and Unicode messages are not supported. The maximum size of a message is 157 Characters. We will break the message into as many parts as necessary if you exceed this maximum.
   
   Sender ID is a local shortcode such as 27199. Marketing, political and religious content is not allowed. Number formatting for Brazil: (Country Code =55), (2 Digits for Area Code), (8 Digits for the number). Note that landlines are being converted to mobile numbers all the time, due to limitations in mobile numbering plan. The porting information gets updated only once per month.

9. Cameroon – For MTN Cameroon, sender IDs which contain both Alpha and Numeric, but start with a Numeric are rejected by the MTN SMSC.ie:
   • SMS123 = delivered
   • 123SMS = rejected
   • 123456etc = delivered
   • SMS = delivered
   
   
   Also, MTN will very likely reject messages with sender ID’s using local numbers and shortcodes that are not assigned to them by MTN or Orange Cameroon. 

10. Chile – Sender ID’s will be automatically changed to a numeric within +5644890XXXX. Handset delivery reports are supported, but please note that in Chile successful delivery rates are unusually high and therefore DLR’s cannot be considered an accurate measure of message delivery. As on all direct connections, no spam, political, and/or adult content is allowed.

11. China – China Unicom (46001)- WAP push messages are not supported. For China Mobile, the use of binary content is restricted. In general, the following restrictions apply for all Chinese carriers:
    • Sender ID will be replaced by numeric local service code
    • Message content-length:
      • up to 65 chars UCS2 or 130 chars ASCII for each non-concatenated SMS 
      • up to 62 chars UCS2 for each SMS if concatenated (not support ASCII)
    • Adults and especially political messages are very likely to be blocked
    • URL links are not allowed in messages. Any messages with a URL will be blocked.
    • Arabic characters cannot be supported into any Chinese networks

12. Colombia – Colombia Movistar (732102) does not provide Delivery Receipts, hence final message status should not be expected. If the number is available at the time of sending the message, it should be considered as delivered.

13. Cuba – CubaCel (36801) has implemented some filtering and it seems that messages are being filtered randomly. We recommend not sending more than 100 copies of the identical message. You must change at least 1 letter in the message every 100 messages.

14. Czech Republic – We are using local direct connections to reach the Czech Operators. T-Mobile and Vodafone are filtering the international routes heavily, so this direct route is the best path of delivery. Sender ID will be automatically changed to a local shortcode to ensure delivery. All other features, such as binary and concatenation, are supported.

15. Democratic Republic of Congo – Messages towards Tigo DRC (aka SAIT) will be replaced with a shortcode as the sender ID. DLRs are supported, as are concatenated, Unicode, and binary messages.

16. Ecuador – DLRs are not provided by the carrier on our local direct link to Movistar Ecuador (74000). However as this is a high-quality direct route, all messages should be successfully delivered. Since 30/09/2012 international senders are required to include an extra 9 between the country code and the local number when sending messages to Ecuador: Country Code 593 + 9 + 8 digits local number (omitting the first 0) Claro 740-01 and Allegro 740-02 are delivered on a local direct connection when messages are less than or equal to 140 characters. Any messages longer than this are terminated on international routes.

17. Egypt – All messages sent have a high risk of filtering imposed by operators in Egypt. Always test a specific case before sending the campaign. Carriers in Egypt do not provide handset delivery receipts. Etisalat Egypt (60203): Filters alphanumeric sender IDs. We suggest using an international format numeric sender ID to bypass the Etisalat Egypt filter. Vodafone Egypt (60202): filters alphanumeric sender IDs, local numbers (both national and international format), and shortcode.ECMS-Mobinil (60201): filters alphanumeric and shortcode sender ID’s. We recommend using an international format numeric sender ID to bypass the Mobinil filter.

18. Finland – Telia Sonera Finland (24491) filters alphanumeric sender ID’s. We suggest using international format numeric sender ID to bypass Telia’s filter. Any alphanumeric, non-numeric, sender might be converted on the intermediate carrier level to an international numeric sender in order to minimize the filtering risk. Shortcode senders may also be converted. Elisa Finland (24405) is filtering on alphanumeric originators and local sender IDs. Message originators will be modified to international format numeric strings in order to ensure delivery.

19. France – French networks don’t allow P2P Carrier to Carrier traffic (or therefore numeric-only sender IDs, to avoid spoofing of identities). AlphaNumeric sender id’s are fully supported. On our direct route, any numeric-only sender IDs will be automatically replaced by “NSMS” except for the following networks:
    
    For Free Mobile, all senders will be replaced by Shortcode 36105. For LycaMobile, all Sender IDs will be replaced with a local French Number. For Virgin (OMEA) Mobile, they allow dynamic Numeric and AlphaNumeric Sender ID.
    
    Special characters in sender IDs are not allowed and will be replaced by character escape. Non-standard GSM characters will be downgraded to avoid breaking the handset display. SFR and Bouygues will only accept messages for delivery between 8 AM and 8 PM local time, Monday to Saturday. Unicode Messages are not supported.

20. Ghana – Tigo (Millicom) Ghana (62003) filters on alphanumeric senderID. We recommend using numeric international MSISDN formatting to reduce the risk of being filtered.

21. Hungary – Handset DLR is supported. The sender ID will automatically be changed to +36707177171 to ensure delivery. Alternatively, you can get your own numeric sender ID which can be used to enable 2-way SMS with your customers. Note that on all direct connections no spam, political, and/or adult content is allowed.

22. India – Messages sent to numbers registered in the NDNC (National Do Not Call) list will be blocked. You can check the destination number on the Telecom Regulatory Authority of India registry. Sender ID is fixed to a local shortcode as required by regulation. We can only guarantee message delivery between 9 AM and 9 PM. We will attempt to send messages submitted after 9 PM, but due to local regulations, these messages may be blocked or queued. Number of messages to the same number limitations: More than 6 messages with the same sender or text to the same number within an hour may be blocked. Users may not be able to receive more than a total of 200 SMS per day across all incoming streams. Messages towards Jammu and Kashmir networks (example, 405/55 – Airtel J&K) will be blocked by the government due to political sensitivity.

23. Indonesia – It is known that carriers in Indonesia are filtering on alphanumeric sender IDs and are frequently sending false positive delivery receipts. We strongly recommend the use of international format numeric sender IDs to bypass Indonesia Carriers filtering. There are some routes to Indonesian carriers where the SenderID will be replaced automatically by a numeric string in the format of an International Carrier to ensure delivery. We strongly recommend using international format numeric sender ID’s to bypass Telkomsel and XL filtering.

24. Iran – Sender ID will be changed to a random numeric string in messages sent to MCI Iran Telecom (43211) Sender ID will be changed to a random numeric string in messages sent to MTN Irancell (43235) Sender ID will be changed to a long number string in messages sent to Iran Rightel (43220).

25. Iraq – Asiacel Iraq (41805) filters Alphanumeric sender ID. We recommend using International numeric sender ID to bypass network filters. Zain Iraq (41820) filters shortcode and alphanumeric senders. We suggest to use international format numeric sender to bypass Zain Iraq filtering. Avoid using senders starting with 46.
    Iraq Korek (41840) does not support alpha sender IDs. We advise you to use numeric senders to avoid this problem. 

26. Israel – Please note, SMS cannot be delivered to kosher phone numbers.“Kosher” phones and networks are essentially phones with Haredi rabbinical approval that can be used for communication without entertainment functionality or connectivity. This is a line that has a pre-defined prefix and it is blocked to content that Haredi activists feel is not appropriate for their community. Such blocking includes cellular internet access, chat rooms, SMS, etc. It should not be imputed that other phones are not kosher according to Jewish law, as evidenced by the fact that a very large number – if not the majority – of observant OrthodoxJews worldwide do not restrict themselves to “kosher” phones; rather the description “kosher” phones is a loose description implying an added level of stringency accepted by some communities. Please be aware that messages must be 160 characters or less.

27. Italy – Italy supports most features, including handset DLR, Unicode, binary, concatenation. It allows only alphanumeric sender IDs and local numeric sender IDs with a maximum of 11 digits and sent in local format. Any SMS sent with an international numeric sender ID will not be sent via the direct route, but rather via international p2p routes. In addition to the usual anti-spam policy, the Italian networks are keen to stress that using a company name in the Sender ID is only allowed when the message is from that company.

28. Japan – The following set of restrictions applies to au KDDI (44007) Japan: Alphanumeric sender IDs will be modified to numeric as KDDI does not allow alphanumeric sender Ids. Concatenated messages currently not supported. If there is an URL in the message body, message delivery will fail. Mobile users can over-ride this by sending an SMS activation command to KDDI. Unicode messages supported, but some handset types are not able to display the content correctly. All DLRs are unreliable SenderIDs for messages to eMobile (44000) will be modified to a numeric string to ensure delivery.

29. Jordan – Zain (Jordan Mobile Telephone Services – JMTS) (41601) filters on alphanumeric sender ID’s, and on the following numeric sender ID’s: 962XXXXXXX whatever the number of digits. Also for other international formats numeric sender ID, please make sure the number of digits does not exceed 11 digits. We recommend using international format numeric sender ID of a maximum of 11 digits to bypass network filters. Advertisement messages require you to add the word “adv” before the sender id e.g. FROM= ”adv Nokia” to be in line with the TelecomRegulationCommission of Jordan. Also, these promotional messages should not be sent after 9:00 PM Amman time (GMT + 3:00). Zain Jordan (41601) alpha senders are dynamic but numeric senders will be overwritten by a fixed numericUmniah (41603) should have dynamic senderID Orange Jordan (41677) filters on numeric senders so all non-alpha senders will be changed to message to ensure delivery.

30. Kazakhstan – GSM Kazakhstan Kcell (40102) filters on alpha sender IDs, shortcode, and local phone numbers as numeric sender IDs. We recommend using international phone number format sender IDs to avoid this filtering.

31. Kenya – Kenya Safaricom (63902) is filtering on alphanumeric sender IDs. We recommend using international format numeric sender IDs to bypass Safaricom’s filtering. Additionally, Kenya Safaricom might send false positives (delivered Delivery Receipts) for messages being blocked by their filters.

32. Kuwait – Zain Kuwait (MTC) (41902) filters messages with alphanumeric or shortcode sender IDs. We, therefore, recommend using international format numeric sender ID to bypass these network filters. In order to bypass filtering, alphanumeric sender ID will be changed to a random numeric string in messages sent to this network.

33. Latvia – Messages with the same content, and sent to the same number within 5 minutes will be blocked by Latvian networks’ SPAM filters.

34. Macedonia- VIP Macedonia (29403) is filtering messages with alphanumeric and shortcode sender IDs. We suggest using an international format numeric sender ID to by-pass this filtering.

35. Madagascar – Orange Madagascar (64602) is filtering heavily in SenderID, Alphanumeric Senders will be blocked and also some Numeric in International format such as: 47xxxxxx, 44xxxxxxxx, 22xxxxxx and most likely other senders as well. We recommend to always test before switching live traffic.

36. Malaysia – Delivery receipts are network receipts and not handset ones. SenderID is changed to a random numeric ID (shortcode) to ensure delivery. Please note that marketing traffic must start with RM0.00 (with a space after the last 0). This is because the end-users should know that they will not be charged for replying to opt-out. If you have not put this in your message the operator will automatically add it and may compromise the maximum length of your SMS (153 characters) therefore we strongly advise you do add this ‘RM0.00′ at the start of your messages of our routes into Malaysia (MCC=502) are fully featured and can support concatenated messages. Unicode and binary. sender IDs are all overwritten with a random Malaysian number or occasionally a shortcode.

37. Mali – Malitel Mali (61001) is filtering in Alphanumeric and Shortcode Sender. We suggest to use International format, Numeric Sender, to by-pass Malitel filter.

38. Mexico – Since local law forbids personalized senders, all senders will be replaced with a random U.S. numeric sender defined by the local carriers. Binary content is not supported. Concatenated messages are supported, as are Unicode SMS. The content of adult, religious, or political nature is strictly forbidden. Delivery receipts are now supported but are still unreliable especially for Nextel (33401)These restrictions do not apply when sending from a Mexican Virtual Number. 

39. Monaco – Monaco Telecom (21201) is filtering in Alphanumeric and Shortcode Sender. We suggest to use International format, Numeric Sender, to by-pass Monaco Telecom filtering.

40. Morocco – IAM (Maroc Telecom) (60401) is filtering in Alphanumeric originators and also might be returning false Delivery Receipts. We recommend using International format Numeric Sender to by-pass IAM filter.

41. Mozambique – MCel Mozambique (64301) and Vodacom Mozambique (64304) are now filtering alphanumeric sender IDs. We recommend using a numeric sender ID to bypass this filter.

42. New Zealand – Telecom New Zealand (53002) is filtering in alphanumeric sender. We will change the sender ID to local shortcodes to ensure delivery. Alternatively, we can procure a dedicated shortcode to gather response messages.

43. Nigeria – Delivery to CDM networks in Nigeria is not officially supported. Messages sent to CDMA operator Starcomms Nigeria will not return Delivery Receipts, but only acknowledgment of message reception by the carrier. CDMA operator Visafone Nigeria (62125) does not provide Delivery Receipts. You should not expect Final Status notifications for messages to this Operator. Glo (62150) does not support alpha sender IDs, therefore all alpha senders will be overwritten by a random numeric in order to ensure delivery. 

44. Oman – As with many destinations in the Middle East, Oman is a difficult market to deliver messages to. Numerous filters are in place to block SMS and even legitimate AtoP traffic can often be blocked. We have a direct route into all networks in Oman (MCC=422) This is a high-quality route that supports handset delivery receipts, and the sender ID is dynamic. Additionally, we strongly advise you not to send messages using Arabic characters as operators often cannot deliver them. We would recommend that you send messages using standard GSM8 in the body of your messages and avoid using Unicode. 

45. Palestine – Palestine is a notoriously difficult destination to deliver SMS to, due to heavy filtering by carriers. In many cases, even legitimate application to person traffic is blocked and so cheap signaling/roaming links do not deliver well particularly for high-value content such as password delivery or alerts. In order to get around this filtering, we use a direct route to all networks in Palestine. This direct connection is fully featured including handset delivery receipts, dynamic sender ID, and delivery to ported numbers. No religious, political, or adult content is allowed.

46. Panama – Telefonica Panama (BSC de Panama) (71402) is filtering in Shortcode sender. We recommend to use International format Numeric sender to bypass BSC de Panama filter.

47. Peru – We offer a direct route to all networks in Peru. For Telefonica/Movistar (71606) the sender ID on all messages will be changed to a local number to ensure delivery. For Nextel (71607) dynamic alpha and numeric sender IDs are supported. For Claro (71610) dynamic numeric senderID is supported. Handset delivery receipts are not supported by networks in Peru. 

48. Philippines – Sender ID for messages to Smart Philippines (51503) is converted to NXSMS to ensure delivery, please note that handset DLR is not supported. Globe Philippines (51501) and  Sun Philippines (51505) support dynamic sender ID, as above handset DLR is not available. Additionally, certain characters are not supported on any Philippines networks.
    
    Officially supported characters are: ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijklmnopqrstuvwxyz % & ‘ ( ) * + – . / : ; ! ” # < = > ? @ 0123456789 € is not supported by Smart or Globe, £ is not supported by Globe, and $ is supported by both. Unicode is not supported on any Philippines networks.

49. Poland – Messages sent to ALL Networks with Numeric SenderID will be converted to “NXSMS”. Alphanumeric Sender is allowed. Sender IDs that contain the operator name (i.e., “Orange”, “Play” etc.) and sensitive Sender IDs (such as “Police”) will be blocked completely. Messages that contain premium numbers and shortcodes in the body of the message will be blocked as messages related to Premium Services are not allowed to be sent via A2P connections. 

50. Portugal – Via Portugal Local Direct Links all Portuguese Carriers do not allow Shortcode Senders. We strongly recommend the use of Numeric Senders in International format or Alphanumeric Senders for all traffic to Portugal to bypass this blocking. Please note that operators are now filtering on Russian numeric senders throughout Portugal. We therefore strongly advise against using any Russian senders into Portugal as messages are extremely likely to be filtered. 

51. Qatar – On our direct connection to Qatar networks: QTel (42701) and Vodafone Qatar (42702) delivery reports are supported and the sender ID will be changed to a short code (97200-97206). Note that as on all direct connections no spam, political, and/or adult content is allowed.

52. Romania – With local direct connections, the sender ID is changed automatically to a local shortcode (17xx-18xx). If you want to use a dynamic sender, you will be subject to carrier’s filter and your SMS might not be delivered. If you need that option, get in touch with us to enable it at your own risk. Anti-spam measures in local direct connections to Romania Networks do not allow to send more than one message to the same MSISDN within 30 seconds. Orange Romania (22610): Only pure A2P traffic is allowed, for example: marketing campaigns, promotions, banking and financial traffic, authentification traffic, different service alerts. Orange requires that customers insert identification information in the body of the message, such as a valid email address, website, or contact phone number. 

53. Saudi Arabia – Dynamic Sender ID is supported, but numeric Senders of more than 11 digits will be blocked. We recommend users to stream messages and/or rotate international phone number originators (e.g. 447565433333).

54. South Africa – Using our local connections towards South Africa, the sender ID will be changed to a local South African Number to ensure delivery. Handset DLRs are supplied by the networks. Unicode and binary messages are supported.

55. Serbia – In order to avoid filtering, all messages to MTS Serbia (22003) with alphanumeric sender IDs will have it replaced by a UK long number.

56. South Korea – Sender ID will be changed to a UK numeric number. Binary and Concatenated messages are not supported. Concatenated messages will be split into separate SMS. Chinese Characters are not supporting virtual Numbers in Korea are only reachable locally. In addition, concatenated SMS is not supported locally. 

57. Sri Lanka – Please note that in order to bypass certain filters in Sri Lanka, particularly to Dialog GSMSAT (MCC/MNC=41302), the sender ID may be changed to a Swedish number. This is to prevent messages from being blocked and to ensure delivery to all networks in Sri Lanka.

58. Sweden – SenderID of messages sent to Telia Sweden (24001) or any of their MVNOs will be changed for a randomly generated numeric string to bypass the Operator filtering in place.

59. Taiwan – Far EasTone Taiwan (46601) is filtering in Alphanumeric originator. We recommend the use of International format Numeric SenderID to bypass the Far EasTone filter. Chunghwa Telecom Taiwan (46692) is filtering in alphanumeric and shortcode senders. We recommend the use of Numeric originators in International format to bypass Chunghwa filtering. 

60. Tanzania – Zanzibar Telecom (Zantel) Tanzania (64003) is filtering on alphanumeric and shortcode sender IDs. We, therefore, recommend using international format numeric sender IDs to by-pass Zanzibar’s filter.

61. Thailand – AIS Thailand (52001) is filtering, both on international carrier routes and on our local direct connection. The filter appears to be triggered by detecting similar traffic from the same sender ID. We would recommend when using a numeric sender ID in the FROM field, to use a pool and round-robin the numbers in the pool. In order to get around this filtering all messages on the default direct route will have their sender ID changed to NXSMS, please contact us to opt-out of this although message delivery will not be guaranteed. 

62. Ukraine – International routes are filtered and there are strict rules on sending from application to person SMS. Due to restrictions on sending certain types of traffic during unsociable hours, we will only deliver on our direct route between 9h and 20h local time. Outside of these times, we will make our best effort to deliver using alternative routes.

63. U.S. & Canada – Carriers do not send handset delivery receipts. Intermediate DLR (accepted status) will be provided as soon as the message reaches the operator’s platform. Binary, VCard, Unicode, and long SMS are not supported by the U.S. carriers. Multipart (concatenated) messages are not supported by the U.S. carriers. However, we will split the log messages in different parts to ensure delivery. Repeated messages to the same mobile number will be blocked by carriers. Only Person-to-Person traffic is allowed in the U.S. An SMS may originate from a mobile phone, a computer, or an internet-based service, but the message must have been initiated due to human interaction. For one way communication, the sender ID will be a random U.S. number. For two way communication, you need to use the incoming number as a sender ID. Alphanumeric Sender ID is not supported in the U.S./Canada.

64. United Arab Emirates -To avoid carriers’ filtering rules, the sender ID will automatically be replaced by a local shortcode: 2018 (towards Etisalat) or 4720 (towards Du). We recommend always testing the actual handset delivery. 

65. Vietnam – Viettel Vietnam (45204) This carrier is currently blocking Delivery Reports, so the DLRs sent are actually network receipts. A ‘positive DLR’ does not necessarily mean the message was received on the handset. It has also been advised against using numbers starting with: 997xxxxxx, 8xxxxxxx, and 6xxxxxxx as sender IDs. We do recommend to use an 11-digit long sender ID. Viettel is filtering on alphanumeric sender IDs, and repeated use of the same numeric sender in the form of an MSISDN. We suggest rotating a random list of International format numeric sender IDs to by-pass their filter. If you do send with an alphanumeric sender ID it will be changed to an internationally formatted phone number from the UK.
    
    Vinaphone Vietnam (45202) This carrier is blocking alphanumeric sender ID, shortcode, and local numbers (in both domestic and international formats). We recommend the use of international formatted numeric sender ID to bypass the Vinaphone filter. Sender IDs on messages sent to Vinaphone will be changed automatically into a numeric string in the format of a UK International format-number (44……) to ensure delivery.
    
    MobiFone Vietnam (45201) This carrier is blocking alphanumeric sender ID, shortcode, and local numbers (in both domestic and international formats). Sender IDs on messages sent to MobiFone will be changed automatically into a numeric string in the format of a UK International format-number (44……) to ensure delivery.

66. Yemen – Yemen Mobile (42103) is filtering on alphanumeric and shortcode sender IDs. We recommend using a numeric sender ID in an international format to bypass Yemen Mobile filtering. Sender ID will be changed to a random numeric string in messages sent to Sabafon Yemen (42101) & MTN SpaceTel Yemen (42102).